I'm not a native English speaker.
Steam does set the prices, in that they use their dominant position to force the best price always being on Steam, whether it's 5 bucks or 100. This is pretty well established in recent lawsuits, whether US courts end up deciding that Steam is doing so legally or not.
In any case, I don't care about price pressure. Games are way too cheap as it is (partially thanks to Steam leaning hard on seasonal sales developers and publishers can't afford to ignore, incidentally).
The stuff that does bother me is Steam telling developers and publishers what to do, what the consequences of not doing it will be and how much of their money they will take afterwards with no recourse. I've seen them do this with my faceholes.
So yes, Steam has a dominant position that harms competition and yes, they do leverage it to do harm. Not to end users, where they're still competing with consoles and effectively with Microsoft, but certainly on the developer marketplace where content creators can't afford to not be in the platform.
Steam uses a Uberified UGC gig economy system on PC game devs where it sets the rules because there's no alternative. And that's bad. More competition makes that less sustainable. And that's good.