Fennec from fdroid, for android, is even better as it didnt originate from google play store. My understandong is Google Playstore injects data into the app package. I use fennec for my day to day access. It syncs with desktop Firefox so all my passwords and logins are there.
There is also Firefox Nightly for "developers". I use it for the custom add on packages and doom scrolling.
Google playstore does not inject data in app packaging because it doesn't own the signature key. F-Droid, however, does.
I mean, they own the signature, but they do not inject or modify apps. They could, though.
Some developers will publish their apps on github, you can download it, and use a different app to get the apk file from the app you get from the play store, and compare the hash of the file. If they're identical then Google didn't meddle with it. If they're not, either Google did, or the developer releases a different version to Google Play.