I’m not too familiar with the details but there is this excerpt from a blog post by Wolfire Games from 2021 where they say this wasn’t the case. Haven’t checked it’s validity or if it’s relevant information to this case, but it is something

When new video game stores were opening that charged much lower commissions than Valve, I decided that I would provide my game “Overgrowth” at a lower price to take advantage of the lower commission rates. I intended to write a blog post about the results.

But when I asked Valve about this plan, they replied that they would remove Overgrowth from Steam if I allowed it to be sold at a lower price anywhere, even from my own website without Steam keys and without Steam’s DRM.

http://blog.wolfire.com/2021/05/Regarding-the-Valve-class-action