The big ones being the popularisation of the licence model for video games, so you don't actually own your games and they can pull your licence at any time.
Loot boxes and child gambling, they basically started that with CS.
They're the ones that popularised early access as a format.
Had to be sued into having a refund policy
Gabe newall is a biollaire that owns a yatch company and a fleet of super yacht, all that money has been skimmed from actual hard working Devs, many smaller ones also have been squeezed into participating in steam sales when they don't want to just to get steam to promote their game. Even thought they will happily push asset flips slop.
They have also put in place system to protect Devs from "review bombing" when those Devs screw over their olayerbase, then will also allow "legitimate" reviews after a human has reviewed them, that are just culture war stuff that has nothing to do with the game.
Valve layoffs on the internet I can only see that they laid off 13 people back in 2019
Because steam has very few employees and basically doesn't make games anymore.