There will no any benefit from using Android instead of iPhone if there's no sideloading.

As for the IDs, I think what happens is that Google sees no need to have hobbyists anymore in the ecosystem. Companies are easier to deal with, easier to change ecosystem to what's needed for Google. While for app development companies, there will be a single enterprise account with some ID used for many developers. And companies just shut up and follow almost any non-financial requirements Google wants to add.

In contrast, opensource developers frequently go public advocating for user privacy and data prorection, while companies tend to be on the same side as Google squeezing any bit of personal user data to sell it for any margin possible.

Is any open mobile device and OS ecosystem possible at this point of time, other than the hobbyist one? With closed gates of LTE/5G ecosystem it seems there's no such possible at all.