From the ones I've been that you don't I can really recommend you Morocco, Turkey and Czechia. All different but amazing at their own styles. It also depends a lot on what you look for when visiting a country. Cyprus is really underrated in my view and I didn't spend one single hour in a beach. Can you do a ranking of the US states you've visited?
Just got back from Cape Town and although it was my first major international travel experience, I absolutely loved it and the surrounding areas we visited.
People there were very friendly and the prices were - in relation to Germany - very cheap.
You have a nice option to swim there in the Black Sea.
But there were many other countries I liked - I didn´t have a holiday that I didn´t like so far.
I've only gone to India, UAE and Bahrain. Gotta admit all three are incredible, Amazing, Awesome, Fantastic, etc, etc
Second on the list would be Paris, especially the artist area around the Sacre Coeur in Montmartre.
Third would be Venice, especially at carnival time in , I think, February.