I'm not saying they don't contribute anything, they dont, they fund others contributions which is just ss valuable, I'm saying their not the champions of Foss when the modification theyve made for their own hardware is pretty opaque by their own design. It's like praising nvidia for opening up their drivers when all they bloody is dis dump code to a public gihtub repo periodically with all actual changes squashed together. As for what they haven't open sourced:

1. The pulse audio configuration that let's the builtin speaker system actually... you know, work. Someone else kindly looked into and contributed. it https://github.com/alsa-project/alsa-ucm-conf/pull/233#issuecomment-1372671325
2. The sddm changes to support the lockscreen code. This is a valve specific feature they forked and have as of yet refused to upstream.
3. The trackpad drivers for the steamdeck/controller touch sensor. You literally have to run steam itself to get this basic hardware functionality working.

I praise valve for their support of Foss projects but that doesn't equivocate their lack of openness on the steamdeck.