Nouveau seems to work pretty well on Debian 13 for me, at least for standard web browser / streaming / video playback with 2160p HDR tonemapping. Back when I was using Debian 12 Nouveau would lag badly during 2160p playback so I was force to use the Nvidia driver binary at the time. But so far it's been alright, granted I've not tested any gaming and perhaps that's where Nouveau won't do as well.