Ionic package build failed - ionic angular toolkit

Build error even after several tries of cleaning the system up from scratch.

Question: What is the best procedure to detect the source problem and fix it.

Build Command

ionic cordova build android ERROR

ng.cmd run app:ionic-cordova-build –platform=android
An unhandled exception occurred: Could not find the implementation for
builder @ionic/angular-toolkit:cordova-build See
"C:UsersusernameAppDataLocalTempng-DhZAYCangular-errors.log" for
further details. [ERROR] An error occurred while running subprocess
ng.

    ng.cmd run app:ionic-cordova-build --platform=android exited with exit code 127.

    Re-running this command with the --verbose flag may provide more information.

Verbose

System Info

Ionic:

Ionic CLI : 6.11.10
(C:UsersusernameAppDataRoamingnpmnode_modules@ioniccli) Ionic
Framework : @ionic/angular 4.11.13
@angular-devkit/build-angular : 0.1001.4 @angular-devkit/schematics
: 10.1.4 @angular/cli : 11.0.0-next.4
@ionic/angular-toolkit : 1.5.1

Cordova:

Cordova CLI : 10.0.0 Cordova Platforms : 6.0.0, android
9.0.0, browser, ios 5.1.1 Cordova Plugins : cordova-plugin-ionic-keyboard 2.2.0, cordova-plugin-ionic-webview
3.1.2, (and 22 other plugins)

Utility:

cordova-res : 0.15.1 native-run (update
available: 1.2.1) : 0.2.9

System:

Android SDK Tools : 26.1.1
(C:UsersusernameAppDataLocalAndroidSdk) NodeJS :
v12.10.0 (C:Program Filesnodejsnode.exe) npm :
6.13.7 OS : Windows 10

package.json

{   "name": "myapp",   "version": "0.0.30",   "author": "",   "homepage": "",   "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e",
    "ionic:build-obsolet": "ionic-app-scripts build android --release --prod  --wwwDir www --buildDir build"   },   "private": true,   "dependencies": {
    "@angular-devkit/build-angular": "^0.1001.4",
    "@angular/common": "^11.0.0-next.4",
    "@angular/core": "^11.0.0-next.4",
    "@angular/fire": "^5.1.3",
    "@angular/forms": "^11.0.0-next.4",
    "@angular/http": "^7.2.2",
    "@angular/platform-browser": "^11.0.0-next.4",
    "@angular/platform-browser-dynamic": "^11.0.0-next.4",
    "@angular/router": "^11.0.0-next.4",
    "@ionic-native/android-permissions": "^5.11.0",
    "@ionic-native/app-version": "^5.9.0",
    "@ionic-native/calendar": "^5.9.0",
    "@ionic-native/camera": "^5.23.0",
    "@ionic-native/core": "^5.21.0",
    "@ionic-native/device": "^5.11.0",
    "@ionic-native/email-composer": "^5.15.1",
    "@ionic-native/fcm": "^5.15.1",
    "@ionic-native/firebase": "^5.5.1",
    "@ionic-native/firebase-x": "^5.24.0",
    "@ionic-native/http": "^5.24.0",
    "@ionic-native/image-picker": "^5.9.0",
    "@ionic-native/in-app-browser": "^5.13.0",
    "@ionic-native/is-debug": "^5.23.0",
    "@ionic-native/keyboard": "^5.9.0",
    "@ionic-native/native-storage": "^5.10.0",
    "@ionic-native/network": "^5.11.0",
    "@ionic-native/open-native-settings": "^5.8.0",
    "@ionic-native/qr-scanner": "^5.6.1",
    "@ionic-native/screenshot": "^5.9.0",
    "@ionic-native/social-sharing": "^5.9.0",
    "@ionic-native/splash-screen": "^5.0.0",
    "@ionic-native/status-bar": "^5.0.0",
    "@ionic/angular": "^4.5.0",
    "@ionic/storage": "^2.2.0",
    "@types/chart.js": "^2.8.5",
    "@types/cordova": "0.0.34",
    "ajv": "^6.10.0",
    "angularfire2": "^5.1.3",
    "animejs": "^3.0.1",
    "calendar-utils": "^0.3.1",
    "chart.js": "^2.8.0",
    "com.darktalker.cordova.screenshot": "^0.1.6",
    "cordova-android": "^9.0.0",
    "cordova-browser": "^6.0.0",
    "cordova-ios": "^5.1.1",
    "cordova-open-native-settings": "^1.5.2",
    "cordova-plugin-add-swift-support": "^2.0.2",
    "cordova-plugin-advanced-http": "^2.2.0",
    "cordova-plugin-android-permissions": "^1.0.2",
    "cordova-plugin-androidx": "^1.0.2",
    "cordova-plugin-androidx-adapter": "^1.1.0",
    "cordova-plugin-app-version": "^0.1.9",
    "cordova-plugin-calendar": "^5.1.4",
    "cordova-plugin-camera": "^4.1.0",
    "cordova-plugin-device": "^2.0.2",
    "cordova-plugin-email-composer": "^0.9.2",
    "cordova-plugin-file": "^6.0.2",
    "cordova-plugin-firebasex": "^7.0.0",
    "cordova-plugin-inappbrowser": "^3.1.0",
    "cordova-plugin-ionic-keyboard": "^2.1.3",
    "cordova-plugin-ionic-webview": "^3.1.2",
    "cordova-plugin-is-debug": "^1.0.0",
    "cordova-plugin-qrscanner": "^3.0.1",
    "cordova-plugin-safariviewcontroller": "^1.6.0",
    "cordova-plugin-splashscreen": "^5.0.2",
    "cordova-plugin-statusbar": "^2.4.2",
    "cordova-plugin-telerik-imagepicker": "^2.3.2",
    "cordova-plugin-whitelist": "^1.3.3",
    "cordova-plugin-x-socialsharing": "^5.4.7",
    "cordova-res": "^0.15.1",
    "cordova-sqlite-storage": "^3.2.1",
    "core-js": "^2.5.4",
    "errorhandler": "^1.5.1",
    "es6-promise-plugin": "^4.2.2",
    "firebase": "^7.22.0",
    "firebase-admin": "^9.2.0",
    "g": "^2.0.1",
    "guid-typescript": "^1.0.9",
    "ionic2-calendar": "^0.5.7",
    "lab": "18.0.2",
    "native-run": "^0.2.7",
    "rxjs": "^6.5.3",
    "signal-exit": "^3.0.2",
    "web": "0.0.2",
    "xcode": "^2.0.0",
    "zone.js": "~0.10.3"   },   "devDependencies": {
    "@angular-devkit/architect": "^0.1001.4",
    "@angular-devkit/core": "^10.1.4",
    "@angular-devkit/schematics": "^10.1.4",
    "@angular/cli": "11.0.0-next.4",
    "@angular/compiler": "~11.0.0-next.4",
    "@angular/compiler-cli": "~11.0.0-next.4",
    "@angular/language-service": "~11.0.0-next.4",
    "@ionic/angular-toolkit": "^1.4.1",
    "@ionic/lab": "^3.2.9",
    "@types/jasmine": "~2.8.8",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "~10.12.0",
    "codelyzer": "~4.5.0",
    "jasmine-core": "~2.99.1",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~5.2.3",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~1.1.2",
    "karma-jasmine-html-reporter": "^0.2.2",
    "node-sass": "^4.12.0",
    "protractor": "~7.0.0",
    "ts-node": "~8.0.0",
    "tslint": "~6.1.3",
    "typescript": "^4.0.3"   },   "description": "An Ionic project",   "cordova": {
    "plugins": {
      "cordova-plugin-whitelist": {},
      "cordova-plugin-statusbar": {},
      "cordova-plugin-device": {},
      "cordova-plugin-splashscreen": {},
      "cordova-plugin-ionic-webview": {
        "ANDROID_SUPPORT_ANNOTATIONS_VERSION": "27.+"
      },
      "cordova-plugin-ionic-keyboard": {},
      "cordova-plugin-qrscanner": {},
      "cordova-open-native-settings": {},
      "cordova-sqlite-storage": {},
      "cordova-plugin-telerik-imagepicker": {
        "PHOTO_LIBRARY_USAGE_DESCRIPTION": " edit user profile "
      },
      "cordova-plugin-calendar": {
        "CALENDAR_USAGE_DESCRIPTION": " add party event to calendar ",
        "CONTACTS_USAGE_DESCRIPTION": " add contact to user "
      },
      "cordova-plugin-app-version": {},
      "com.darktalker.cordova.screenshot": {},
      "cordova-plugin-x-socialsharing": {
        "ANDROID_SUPPORT_V4_VERSION": "24.1.1+"
      },
      "cordova-plugin-safariviewcontroller": {},
      "cordova-plugin-inappbrowser": {},
      "cordova-plugin-advanced-http": {
        "OKHTTP_VERSION": "3.10.0"
      },
      "cordova-plugin-email-composer": {
        "ANDROID_SUPPORT_V4_VERSION": "27.+"
      },
      "cordova-plugin-android-permissions": {},
      "cordova-plugin-firebasex": {
        "ANDROID_FIREBASE_ANALYTICS_VERSION": "17.0.0",
        "FIREBASE_ANALYTICS_COLLECTION_ENABLED": "true",
        "FIREBASE_PERFORMANCE_COLLECTION_ENABLED": "true",
        "FIREBASE_CRASHLYTICS_COLLECTION_ENABLED": "true",
        "ANDROID_ICON_ACCENT": "#FF00FFFF",
        "ANDROID_PLAY_SERVICES_TAGMANAGER_VERSION": "17.0.0",
        "ANDROID_FIREBASE_MESSAGING_VERSION": "20.0.0",
        "ANDROID_FIREBASE_CONFIG_VERSION": "19.0.3",
        "ANDROID_FIREBASE_PERF_VERSION": "19.0.1",
        "ANDROID_FIREBASE_AUTH_VERSION": "19.1.0",
        "ANDROID_CRASHLYTICS_VERSION": "2.10.1",
        "ANDROID_CRASHLYTICS_NDK_VERSION": "2.1.1"
      },
      "cordova-plugin-camera": {
        "ANDROID_SUPPORT_V4_VERSION": "27.+"
      },
      "cordova-plugin-is-debug": {}
    },
    "platforms": [
      "browser",
      "android",
      "ios"
    ]   } }

What I tried
without success.
Deleting node_modules manually (then npm i), restarting systems and use of commands below…

ionic repair
npm i @angular-devkit/architect@latest @angular-devkit/build-angular@latest @angular-devkit/core@latest @angular-devkit/schematics@latest

npm uninstall -g @angular/cli
npm cache verify
npm install -g @angular/cli@latest
npm install

npm i @ionic/angular-toolkit

npm audit fix
npm audit fix --force


npm update
ng update
ng update @angular/cli
ng update @angular/core

Ionic Serve Additional error info on ionic serve:

[ng] Schema validation failed with the following errors:
[ng]   Data path "" should NOT have additional properties(es5BrowserSupport).

[ERROR] ng has unexpectedly closed (exit code 1).

        The Ionic CLI will exit. Please check any output above for error details.

[ng] Schema validation failed with the following errors:
[ng]   Data path "" should NOT have additional properties(es5BrowserSupport).