After kernel update 5.13 -> 5.15 system wont boot

you cant just manjaro-chroot -a into encrypted system

OK then I canā€™t help.

As i pointed earlier, i thinking the information of the currently running kernel is misleading.
Iā€™d go with chrooting as you managed to so far, and just reinstall the driver.

sudo mhwd -r pci video-nvidia
sudo mhwd -i pci video-nvidia

I already tried that. It was searching for the 5.13 drivers and couldnt find them if I remember correctly, so I installed video-linux instead which still didnt help.
Anyway I gave up and reinstalled the system, because I needed the laptop for school.

It was searching for the driver because you didnā€™t remove the unsupported, inexistent, kernel 5.13.
It couldnā€™t find them (and why you broke your system) because the drivers for this unsupported, inexistent kernel, donā€™t exist anymore in Manjaro repositories.

Now on your fresh system make sure you use a LTS kernel (kernel 5.15 for instance), and if you donā€™t, make sure you follow the announcement threads to keep informed of End Of Life of non LTS kernel and remove them before they are removed from Manjaro.

well if I correctly understand this thread mhwd tries to install the drivers of the current running kernel and the host kernel is seen as the current running kernel when chrooted. So this probably wouldnt work regardless, because the live system I was on was still 5.13

Possible, to be honest I never used an old outdated ISO to chroot so maybe this was the issue, but that is the first time I read about that so I donā€™t know, it seems weird. MHWD in theory install the modules for all the installed kernel of the system (so here I assume of the chrooted system) as far as I know, but maybe there is a special issue with chroot when the live environment has unsupported kernel. But still that wouldnā€™t make sense if MHWD would try to install modules for a kernel not installed on the system.