Hidden holiday gems in Europe?

Have found myself with a week free early July and looking to book a trip somewhere in Europe.

Peak summer season I know but any underrated spots that wouldn't be tourist-centric? Ideally looking to travel round by renting a car, spending 2 days or so and then moving somewhere else. Prefer small towns/countryside than larger cities.

Had looked at Tuscany but car rental and flights were coming to near €800 before anything else, and accommodation wasn't looking cheap either. Again, I've limited expectations given it's high season but any places off the beaten track I should consider definitely welcome!