Even with your clarification, I think I touched on that. Steam isn’t trying to push companies to develop for Linux, instead they are trying to make Linux more compatible with games. That’s why they’ve talked wine and turned it into a very game specific thing called proton.
If they wanted to push people to develop for Linux, they wouldn’t put so much time and effort into developing something that removes that need
The guide lists a bunch of things, are you trying to undo them all? If so, how come? If you’re looking to sell the steam deck, doing a factory reset might be the better choice