Where to travel in Europe November - January and meet young adults?

I’m a single 33M from Australia, I make well over 10k/mo working for an American company so money isn’t a huge issue. I’ll soon have a Polish citizenship by descent also.

Looking to have a good time and make genuine connections with other young adults similar to my age. I was in Eastern Europe earlier this year (Czech, Hungary, Poland) and liked it, but I had trouble finding and making friends in my age group.

Im looking for recommendations for warmer climate countries this time of year… as well as social events or experiences where I can meet new people. I enjoy music, art, festivals, going out etc. I generally find clubbing and going to bars result in very shallow relationships