Sorry to jump in here, but I’m wondering if you’ve seen any progress on this?
In general, everything works well on my 12th gen, with Debian testing/bookworm. Except Signal Desktop. Firefox, everything else works fine under i3 with a composition manager (compton), but there’s tearing/shearing in Signal, and I don’t understand why. Interestingly, I’m seeing the same problem in Chromium… It’s pretty nasty!
I probably should try under Wayland but ugh, another thing!
Update: turns out the fix is simple, just pass the --disable-gpu-compositing command-line switch to signal-desktop or chromium, see also this post. This can be made persistent by adding a file in /etc/chromium.d/disable-compositing:
export CHROMIUM_FLAGS="$CHROMIUM_FLAGS --disable-gpu-compositing"
That, obviously and unfortunately, doesn’t work in Signal, which I run from Flatpak, which doesn’t support such overrides. Arghl. I had to fix a wrapper scrip to have this work. See also this commit.