because new shaders are available, essentially shaders matching your card will be provided through steam, steam will send unique shaders created on your pc to them so that it can be sent to the other users with the same hardware too. this is why games with steam workshop mods tend to get very big shaders if they are popular or have a steam workshop showcase on rotation as those shaders get included too.
I also enjoyed it! And I'm happy to use bazzite ^^ But what I still don't get ... how does bazzite have a tiny bit less performance (on desktop PCs)
I also read about the various patches + steam is included in the base image, no flatpak and there is a little bit less performance.. even all the kernel patches and the system76 schedeuler