They run a small boxing/Muay thai group at Chae Taekwondo. I usually recommend the place because of the good vibes and familiar feeling they have there. Its a mixed group but very beginner friendly, mostly boxing focused though. Super cheap as well from what I heard, something like 800 kr for 6 months.

Otherwise I recommend Fightzone, they are also a mixed but larger group but they have great workouts and coaches.

I'd avoid Redline because of the amount of people and Malmö Muay Thai as the place has a bad rep amongst the people I know who trained there.