I've never had issues with my Debian or Devuan machines, UNLESS they are multi-monitor. (Course I am using Wayland.) Bullseye, Bookworm, even before that. Probably going back to Jessie (and Ascii for Devuan.)
However, In Wayland, there is still the issue where if you have multiple (physical) monitors, "fullscreen" assumes the entire space of all those monitors.
(This is not a problem unique to tic80; this also happens, for example, when using waypipe and creating a fullscreen application. I believe there's an underlying issue where "fullscreen" means one thing in X and another in Wayland, and getting past that may break X. Since most folks just won't move on from X, I understand not spending a lot of time on the wayland fix.)
A workaround is to just trigger "fullscreen" using your window manager, which doesn't hook the same "fullscreen" code inside tic80. And yes, this works with the CRT look.
(And that problem also exists in Void, which is my daily driver. )
So unsure where you're coming from with "working" - it certainly didn't seem completely broken, and it doesn't seem completely fixed either.
It is _usable_ and has been for years, in my opinion.