For adventure, try an Explore or Exodus holiday to Morocco or similar. Inexpensive and very memorable. Desert camps, camel rides, ancient sites, souks etc.
For something calmer I agree Slovenia is amazing. Ljubljana is clean, safe, pretty. A gorgeous city with a funicular, castle, great markets and cafes. Lake Bled is perfect for cycling, swimming, kayaking, boat to the island, another castle, Tito's summer palace is now a tea shop ( in high season only iirc) Lake Bohinj is sapphire blue and jade green. Great hikes around the lakes, water sports, hang gliding for dare devils. Everywhere us clean, safe, beautiful, easy to reach.
Or a long city break in Budapest. Explore the amazing spas, dating from Roman times to 1930s glamour. There is a secret wartime hospital hidden in Buda caves, now a .museum, a church in the caves, the old ruin bars, Danube cruises, Margrit island with hire of all sorts of bikes and carts, and a mudical fountain, indoor markets, animal cafes. When we went there was a brilliant music festival on. And you can take a trip out to the bear sanctuary to hand feed honey to the bears.