Still no luck 
I first tryed completely removing MSFS and reinstalling, this is on my nvme drive. I have 3 drives, a 2Tb nvme where Windows and MSFS are installed, a regular 500Gb SSD not doing anything and a regular 2Tb HDD. While it was installing I had a thought that one of my drives might be failing so when FS tries to access some file it struggles and stutters. I did a scan of my drives and they were all working fine though.
When the installation finally finished I ran it and it was still stuttering as before so I decided to do another removal and reinstall, this time on my SSD. If anything the stuttering was worse. So in summary I have done 2 complete reinstallations today and neither helped in the slightest
I did find this post which does sound very simialar to my issue:
He has written a big list of things he tried (most of which I tried). Only thing that fixed it for him was reinstalling Windows. An absolute last resort for me.
Only thing that helped me once was disconnecting my ethernet cable so I might try that later again and some other related things.