[Vlim]

There is no slide on a P08, so also no slide stop.

Your L-shaped holdopen should normally lay flat.
It now has a weird angle which suggests either it or its leaf spring are compromised.

Try pulling it out from the rear, or pushing it down.
The take down lever can be pushed out from right to left when it is facing downwards. It may give you some extra wiggle room.

I think the holdopen spring broke and is jamming the upper.
Some wiggling and gentle tapping may do the trick.

Also try pulling the receiver backwards so the holdopen can be manipulated through the magazine well.