I am shocked that Facebook employees even see this as a vulnerability. I always considered metadata the valuable part of WhatsApp.

In that case you still have the third party bridge https://github.com/emersion/hydroxide

A separate routing table that takes precedence over the one modified by DHCP should works as well I think. Oh, and of course you have to use a vpn that forces its own nameserver or set one manually to prevent redirections.

If you need arm, then you probably have to install libhoudini https://github.com/casualsnek/waydroid_script

There are Browser extension available, i do not know their quality.

There seems to be a Firefox extension that can send downloads and start jdownloader as well

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.

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.