AMD/ATI RS780 (Radeon 3000)

Same here! I use AMD RS780/RS880 HD 4200 as well. I had same issues with installing Triskel, PureOS and Guix system. Furthermore, Aramo made graphics faster and more stable; Here is my benchmarks:

Trisquel Nabia:
1- $ glxgears benchmark: Full screen:11fps - Windowed:117fps
2- Graphics caused frequent system crashes, specially on Abrowser
3- Sleep/hybernate function was buggy and made screen look very weird and unusable
4- Games (like Teeworlds) have very low fps (6fps), Although run without problems

Debian Bullseye - Gnome (with only free software):
1- $ glxgears benchmark: Full screen:58fps - Windowed:385fps
2- Sleep/hybernate function was buggy and made screen look very weird and unusable
3- Games (like Teeworlds) also made AMD drivers fail and screen look very weird

Trisquel Aramo:
1- $ glxgears benchmark: Full screen:46fps - Windowed:310fps
2- Sleep/hybernate function work perfectly
3- Games (like Teeworlds) have low fps (16fps), Although run without problems

After long time not being able to watch any movie on my computer (because of low FPS), I am very happy to have my graphics work so good! Thanks Trisquel developers! I just wished you could work with Debian, so that Aramo gets even better GPU performance and Debian gets the stable graphics like Aramo!

You can try the libre driver PPA bacport for Aramo:

https://launchpad.net/~oibaf/+archive/ubuntu/graphics-drivers

sudo add-apt-repository ppa:oibaf/graphics-drivers
sudo apt-get update
sudo apt-get upgrade

You won't get hw acceleration but you might scrape more FPS due to LTO optimizations and faster code in MESA.