Oh! I had wanted to make something like this, awesome!

yep! Since I got the phone I got, I have never logged in to Google. Just gotta hit ‘Skip’ on the device setup - and you can download a .apk of the aurora app store and use it anonymously, in addition to using f-droid (tho, caveat, folks have opinions about f-droid) https://f-droid.org/packages/com.aurora.store/

you can use android without being logged in to google. Especially using the Aurora app store