Rubberduckzilla Also what non google app store is it advised to use?
If you don't want to use Google Play Store because it requires an account, there's also Aurora Store, which allows you to access it by providing you with one of their accounts.
I do have to mention, though, that Google Play Services and Google Play Store do not operate the same way they would on Stock OS, in case this is what's holding you back. They're regular apps just like all other apps you'd install on your device and have no special privileges at all. To learn more about this, you can read this section:
https://grapheneos.org/features#sandboxed-google-play
Beyond that, the app store situation on Android right now is not great. A lot of people choose to get their apps directly from the source (GitHub or GitLab) and keeping track of updates for them by using Obtainium.
There is also a very promising app store that's being developed called Accrescent but it is still in development and not yet ready to be used.
I would specifically advise against F-Droid, as it has numerous security issues that make it a poor choice for someone concerned about privacy/security which you can read about here.