Official YoYo Games FAQ said:
Can I get GameMaker Studio 2 on Steam?
GameMaker Studio 2 is not currently on Steam.
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Source)
GMS 2 is still in its Beta stage, so things will constantly change. Although there's no Steam version of the product available at the moment, there
might be one in the future. When YYG are willing to share information, they will do it themselves. So there's a little use of this discussion right now, as it would hardly make a difference.
Also, I believe you can already view the amount of time that you have been using the IDE for. But if that's not the case, feel free to file a suggestion.