They are entirely intertwined.
There is absolutely nothing intertwined about timed exclusivity and marketing on a platform you have yet to release on. There have been plenty of games with staggered PC launches or console exclusivity for a limited amount of time that have a Steam store page pushing marketing materials either before the console version releases or after the console version releases, but before the Steam/PC version releases. This is a non-issue.
This is only being made into an issue because "Metro exclusivity bad" and "Epic bad" discussion (which, Metro exclusivity is bad) is bleeding into this discussion and being conflated with it. If your intent is to point out that Epic lacks the ability to push marketing materials on the Epic Games Store, that's absolutely a fair criticism of their platform. I don't think, however, that it is backwards of Deep Silver to continue pushing marketing materials on a storefront that their game will come to in 2020. My assumption is that even if there was a place on the Epic Games Store to market in such a manner, which there absolutely should be, Deep Silver would continue to also market on the Steam storefront as well.
If you are trying to bring exclusivity into the conversation to point that Deep Silver signed an exclusivity deal with a company and storefront that doesn't even have a place to market games like this, then this is really no different than any other thread discussing the Metro exclusivity deal as it is simply another facet of it. Deep Silver marketing the game on Steam though isn't an issue given the eventual release to Steam. And, as you said, it isn't an abuse of the publisher/developer agreement because, as I've highlighted previously, plenty of other developers engage in this same practice (marketing on Steam when they're already releasing on a console/platform) too.
In truth, I don't understand why any consumer cares if the game has marketing material posted on Steam or not. It doesn't impact the consumer in any way. Yes, the exclusivity does, but as I addressed previously if you're simply using this to further criticize the Metro exclusivity deal, then this thread should be closed and brought back into the general Metro exclusivity deal discussion.
