In case you haven't noticed already, the firm and the people who filled this case have no real base for the case and their "proof" is basically social network content which doesn't include a single official document, nor from Valve's Steam service (which all developers have access too) nor from other developers, aside of that, they don't even make any sense with the companies they included in this process, Ubisoft abandoned the platform in 2019 so the prices can't possibly be manipulated by Valve in any way, more so that they can even make it cheaper in their own service because it could drive more customers there and increase EGS prices.
What the heck, let's make this even more simple, Steam is a platform in the same sense than PSN, Xbox Live, Eshop or any other launcher, how is it possible that a single platform determines the base price of products over publisher/developers choices? it's simply not possible, all what is included in the contracts and the official documentation is a series of suggestions that you can follow but they won't ever tell you how to set your prices, in any case they could ban you if they detect you are doing weird movements within their serives (generating keys) and doing something fishy outside Steam.
So yeah, this is an absolutely broken process and I don't really see a way of this progressing in a favorable way to the firm and the particulars, in any case what devolver answered should be enough to clarify where is this going to land, process will probably end without any repercussions to Valve and the other companies because, from the very beginning, this seems like a cash-grab case or worse, a troll case.