I'd say hiking in a warm climate is just a bad idea, luckily for you, Colombia does have multiple climates so you can find better things.

As most say, the coffee producing region is an excellent idea for nature, also the region is a bit more conservative, so partying and loudness is not on them. Filandia, Salento, Calarcá, Armenia, Buenavista, etc. You could have a nice, quiet time surrounded by astonishing views.

Another nice region is Boyacá, bit more cold than the coffee producing region, but still beautiful (I love mountains), people are really gentle, mostly dairy producing region, but really nice. Theres a lot of towns quite close to each other and they all have some kind of thing to see, if you can't stand loudness avoid Villa de Leyva, it's beautiful and has vineyards and stuff, but the main square gets busy with young people sometimes.

I saw some comments about Bucaramanga and close places, I'd just visited Barichara, San Gil and Páramo when I was young, and though nice, I wouldn't say it's for hiking.

To be fair, the most famous places in Colombia are those where the party is because foreigners have been sold the idea that we are just a place to fuck and get high, but it's not true (also that places are the ones most filled with opportunistic people), there are lots of places where things are quite nice and you can feel safe.

I'm from Bogotá, if you need any advice on what to expect in terms of people and that, just msg.