Obviously that was a massive red flag for me, but the search for alternatives gave me a good impression on how massive Google actually is. Many developers don't even seem to consider any alternatives for AdMob/AdSense.
So far the best alternative I was able to find seems to be MoPub and to use their mediation capabilities. I really don't want to go all in on Google, but especially when working on mobile, it often seems like there are not too many choices.