There is a public transport app called Öffi which I consider essential when in Germany. It is free, does not gather data on its users and covers the entire country, the alternatives are regional and many really want to know all about their users.
That link is to the Google Play Store, but it has twice been removed from there.
The first time it was because the app encourages donations, but that request was hidden from users installing via the Play Store. I think Google looked at the app and noticed that request for donations but could not see that it was functionally inactive. It took them a few months to accept the truth and permit the app again.
The second time was mid July 2025, they banned it again and refused to say why. I was in Germany and travelling at the time, the app ceased working with a database error and I was screwed, it took me a day or three to download Fdroid and get it working but now I get it from there. It's back in the Play Store (I don't know when that happened) but I have to assume this idiocy is going to happen again.
I use another App where the developer(s) announced that they were going to stop updating their Play Store version because the overhead was just too much, and that the preferred migration path was to Fdroid. It is a security product, one which resolves QR codes to text and requires the user to confirm that they really want to visit that site. Works for me.