A week ago my trunk would not open/close all the way and got quoted 800$ to replace a strut. Fixed the old one easily my self (you can do this too in an hour if you have the same problem)
Posting the problem and free fix here for future reference, and link to the process I posted on the official polestar forum.
Having found a post on Polestar forum (the official forum on polestars own site [link in post]) showing how to easily replace a faulty strut yourself with a used OEM part for 150$ I saw a guys who said to always check the wirering going between the struts and the car, since these are known to be “pinched” and snap.
Using a cheap OBD scanner and the app “V-tool” (specifically made for Volvo-cars error code aka Polestars included) I was pretty easily able to get error codes from the car (had to get a one week subscription for V-Tool for 9$, so yeah, not completely free). The errors showed some problems with sensors on “right side POT” (Power Operated Tailgate). Peeling back the rubber protection on the wires going from the strut to the car body, I could see that a blue wire was completely snapped in two!!! Removed the panel in the trunk (the one with the speaker) unplugged the little plug connecting the strut to the car (a little fiddly but doable) and pushed out the wire through the car body. Takes 10 min. Soldered the wire and shrink wrapped it. Reversed the whole operation and VOILA! It works again like new. Saved me about 800$ and a trip to the service centre. If this happens to anyone else, CHECK THE WIRES FIRST! You can do this even with out the OBD-scanner, you just have to check both struts then, which is easy.
Hope this helps any future Polestar owners with the same problem.