Webcam in Ubuntu 20.04 works partly

My webcam works in some applications and does not work in another.
For example, it works in skype and guvcview but does not work in cheese (cheese was reinstalled, no effect).

>lsusb
Bus 001 Device 002: ID 0806:0806 SJ-181217-N 1080P Webcam

>hwinfo --usb
07: USB 00.2: 0000 Unclassified device
  [Created at usb.122]
  Unique ID: RUmI.YLn6RqfXaa3
  Parent ID: k4bc.2DFUsyrieMD
  SysFS ID: /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.2
  SysFS BusID: 1-7:1.2
  Hardware Class: unknown
  Model: "SJ-181217-N 1080P Webcam"
  Hotplug: USB
  Vendor: usb 0x0806 "SJ-181217-N"
  Device: usb 0x0806 "1080P Webcam"
  Revision: "12.17"
  Driver: "snd-usb-audio"
  Driver Modules: "snd_usb_audio"
  Speed: 480 Mbps
  Module Alias: "usb:v0806p0806d1217dcEFdsc02dp01ic01isc01ip00in02"
  Driver Info #0:
    Driver Status: snd_usb_audio is active
    Driver Activation Cmd: "modprobe snd_usb_audio"
  Config Status: cfg=new, avail=yes, need=no, active=unknown
  Attached to: #9 (Hub)

Even more, in chrome it works on some websites and does not work on another. I don’t know if that is the same issue or another one. It works in meet.google.com and hangouts.google.com and in some webcam tests, but it does not work in any of the javascript webcam tutorials (where we use <video> and navigator.mediaDevices.getUserMedia(..).

If I google for webcam test, and follow the results:

1. https://www.onlinemictest.com/webcam-test/ – works;
2. https://webcamtests.com/ – does not work;
3. https://www.vidyard.com/cam-test/ – works;
4. https://webcammictest.com/ – does not work;
5. https://www.iobit.com/en/webcam-test.php – works;
6. https://www.hotcleaner.com/webcam-test/ – does not work;
7. https://www.drift.com/video/camera-test/ – does not work;

Chrome devtools says nothing.

Update:
got a very strange behavior: If I go to any of the working websites, for example to https://www.onlinemictest.com/webcam-test/ and start the test, then in the other tab open non-working site, it starts working as well.
It seems, the working website makes something that turns the camera on, and after that it works everywhere. If I close the first tab and refresh the second, I see the black screen only.