30 seconds arent that bad.

I once was forced to a five minutes video. Five minutes of pure cringe can feel like hours.

I suggest you Organic Maps. Lightweight, offline, FOSS. Maybe not as much functions as maps but enough for me.

TrackerControl on FDroid can even block trackers in apps that need internet.

You can untick the other providers. I found this one for example.

25€ for 15G is also way too much. I now pay 5,99 for 7GB. (Also germany, monthly cancellable, sim.de [No advertisement])

You should look here for good prices.