Wanna give a source for that? Everything I read said that after the 24 hour scare screen, you could optionally enable third party installation permanently. Literally nothing about certificates expiring. Where are you even getting this from?

I don’t know why you are so insistent that everyone who mentions Windows is using a online account, but you actually do not need a google account to use an android device in most cases. I have been using android phones with no logged in account, with side loaded app stores and independent apps for years. Maybe the mainline flagship devices enforce it; I haven’t had that problem personally.

Google would really like to crack down on installing software without their permission, and they still track every bit of information they can with the Google Play API even without an account, but I digress. I haven’t had a google account in several years. Or a Microsoft account either, for that matter.