How do i update whonix-gs and ws-16 in Qubes 4.1? And which template should i have when using debian as default?

I would either wait for sometime and try again, or would comment in fasttrack source in the sources list so to be able to update template from other sources, and then investigate what could go wrong with fasttrack.

I tried to follow for what @51lieal suggested, but I can’t install whonix from the qvm-template-gui. I tried to select both the whonix-ws-16 and whonix-gw-16 and hit “apply”, but when the “installing templates…” window pops up, I immediately have 100% and nothing is listed and there’s only option to click “ok”.

try left clck and hold down in the template you wanr, then release in install, after that click apply

That doesn’t do anything. Besides, it does imitate installation when I click on “apply”, it just doesn’t install anything. Just 100% and that’s it. nothing is added

Operating System Software and Updates chapter fasttrack repository issues in Kicksecure wiki
(Whonix is based on Kicksecure.)

You could found that with a search engine query with the following or similar search term:

site:whonix.org fasttrack is not valid yet (invalid for another