Magento 2 - How to add custom JS file path into CMS Block

In Magento 2, you need to add and declare your js file via RequireJS

So:

app/design/frontend/Codazon/fastest/requirejs-config.js

var config = {
    map: {
        '*': {
            myscript: 'js/my_custom'
        }
    }
};

app/design/frontend/Codazon/fastest/web/js/my_custom.js

define(['jquery'], function($){
   "use strict";
       return function myscript()
       {
           alert("Yes, it woooorks!");
       }
});

app/design/frontend/Codazon/fastest/Magento_Theme/templates/{yourfile}.phtml

    <script>
        require(['jquery', 'myscript'], function($, myscript) {
            myscript();
        });
    </script>

PS you also need to:

• clean the cache => php bin/magento c:c

• clean var/view_preprocessed content => rm -rf var/view_preprocessed/*

• clean pub/static content => rm -rf pub/static/*

• deploy the static content = php bin/magento setup:static-content:deploy -f

Good luck!