Used car 5000-6000€

Hey guys i need help with buying a car. I live in Serbia and i would like to buy petrol car, (maybe even with tng) that is with maximum 2000cc engine but i am totally lost. I dont want to buy grandpa with 300k+ km, and for sure dont want to buy cans with 900cc engines that includes seatbelt as an option. Love retro cars, love wagons, love quirky cars... Any advice is welcome. Thank you... 🙌