Husqvarna FE450 clutch broken?

Hi, I recently bought a Husqvarna Fe450 (model year 2023/new).

After the first few hours of use, I had the problem several times that when shifting from 3rd to 4th and from 4th to 5th gear, a kind of "intermediate gear" would often slip in. Then my bike would rev up but not accelerate until the gear automatically jumped back into place.

A short time later, I started having to warm up the engine for several minutes at idle before I could shift into first gear. If I didn't do that, it would stall even with the clutch pulled in…

Today, while I was riding, one of those "intermediate gears" slipped in again, and since then the Husqvarna hasn't accelerated properly, only at very low revs.
It feels like the clutch is slipping.
Also, my clutch lever has started squeaking since the incident, so that might be related.

Maybe there is someone who has the same problem with this or a similar machine. Unfortunately, I'm a total newbie and don't know much about it.

I would appreciate it if someone could help me figure out how to solve this, whether I need a new clutch or whether it is just out of adjustment.

Thank you very much <3