These games are such a small portion of the overall steam playerbase I’m not sure why Valve would care. Everyone makes such a big deal about like 4 or 5 games that dont run because the devs have explicitly chosen to not allow it.

From the article:

Other major titles, such as Call of Duty, Battlefield 6, Valorant, League of Legends, and Fortnite, also cannot be played on Linux. For many players, that immediately rules out Linux as a viable platform.

Like 3 of these 5 games mentioned are not even available on steam. Why is this on Valve to fix?

You are looking for gdctl. https://manpages.ubuntu.com/manpages/plucky/man1/gdctl.1.html

You may also want pactl for audio switching.