I cannot use my (good) Logitech 922 USB Webcam

[Sven]

Is there a way to upgrade to that R4.1 Alpha version?

Nope. Needs to be a fresh install. But you could backup/restore your qubes.

Signed Q4.1 alpha iso

Here is the long requested alpha build: https://ftp.qubes-os.org/iso/Qubes-R4.1.0-alpha20201014-x86_64.iso and its signature: https://ftp.qubes-os.org/iso/Qubes-R4.1.0-alpha20201014-x86_64.iso.asc. This isn’t “release candidate”-stable yet, but most of the things should work already.