I would like to meet native German speakers.
Do you know anything about a forum or a group where I can practice my German?
I can't recommend anything for personal encounters, but I'd like to suggest participating in forums about topics that are of interest to you. For example, there is something about
Running, fitness: https://forum.runnersworld.de/forum/
(These are just ones that I take a look at occasionally).
I love your profile picture!!! I literally just watched that lol
And as far as getting better at German, you can start a club on duolingo to speak to others as you probably already know. And here is an extra tip to help you learn it better too, listen to some German music! :) https://www.fluentu.com/blog/german/famous-german-singers/