The pkgbuild should not depend on it if you build in x64, that is only a display Problem in the web i think. Firefox should be avle to download its own copy of widevine though.
progandy
Glibc-widevine is only needed on arm and the aur comments have a link.
The mobile device / "mtp Server" requires the gadget mode as far as I know. The PC /client does not need it.
With usb-c you should be able to load a driver that allows network connectivity regardless of otg mode. Or was it Thunderbolt?
Update: I thought of thunderbolt-net which works with Thunderbolt 3 and probably USB4
There is or was a project called WinApps i think that made it easy to set up a VM to run some applications.
Porteus kiosk thin client might be an option.
repo-add cannot create empty repositories anymore. I suggest you add the aurutils package you already built to the initial repository and database.
Other formats can exceed that by caching & writing to multiple chips at once i guess.
I had at least hoped for FastStream. (Essentially bidirectional SBC for good quality audio while using the microphone)
Auf dem Desktop kannst du behelfsweise einen anderen web client verwenden, z.B. https://alexandrite.app/feddit.de
There seems to be a Firefox extension that can send downloads and start jdownloader as well