At least with "Sign in with Apple" you can choose to give a random alias that forwards to your email. I do this for every single service I sign up for. Completely unique Email + password for everything.

It's built into Android/iOS and an accepted way of logging into an app. The app store page (when it's released) shows exactly what I need: practically no information at all.

Google handle the payment and the subscription too (same with Apple) and that's a very common pattern too.

I understand the skepticism though.