I can’t claim to know what Google/Admob will do … but here goes …
You are essentially asking whether user action in one game can benefit them in another game.
I don’t see why this should be prohibited - esp. if the IAP is benefitting Google (their 30% share of it).
You are not exercising any obvious “unfair” advantage by doing so - except for the fact that a user of your one game may prefer to use your other apps (because they can leverage their earnings from the other game in this game).