@Tutanota You can still switch to Graphene or Lineage, and I suspect removing Google Play Services and all Gapps will likely disable this too. If new phones become 100% locked, the value of "pre-ban" phones will skyrocket on Ebay et all and a cottage industry of modifying old phones to use any available battery may well be born. That is a job I myself have done in the past.
As of a month ago, the ability to install unapproved apps by the ADB bridge over USB is also supposed to stay in mainstream Android.
What may very well happen is that Google apps and unapproved apps could down the road be unable to coexist in the same phone. Google could severely limit any app's uptake simply by making it impossible to run it and Google Play Services at the same time.
I have do-Googled many phones before I switched away from mainline Android entirely, and it takes hours and the job grows as Google moves more stuff to the closed source Google Play ecosystem. You may have to not only kill the search assistant and replace Google Maps, but replace the keyboard app too.
Chat Control could limit Signal to use inside fighting groups or other high-privacy users simply by demanding Google ban Signal, and then ensuring that anyone installing Signal has to delete Google Maps from their phone to get rid of Google Play Services.
Won't stop me, but could mean I can only talk to a few other people who follow me all the way out.
Google also cannot as easily control phones being treated as dumb wifi hotspots with the unapproved programs run on real computers. Anyone can do that assuming they already know how to tether, no hacking required. People may have to start carrying laptops again like I did for so many years.