Looking at possibly doing a trip to Europe in April/May of 2026 with my wife. Looking for recommendations of where to go!

I am considering going to Europe in April or May of 2026 for 5-7 days from the U.S. I don't love large crowds, and I'd really prefer not to have to worry about pickpockets or other petty crime. I'd like somewhere with good culture and good nature! I would prefer the country to be on the budget-friendly side, but it doesn't have to be. Right now, I have Slovenia, Croatia, or Austria on my mind, but I'd be open to other countries like Poland or the Baltics. Would any of you happen to have any advice or places that meet my criteria?