i am going to follow this as i am having a similar issue (on multiple distros even and with nothing helpful in the journal either). i went as far as to replace the entire PC, suspecting a hardware issue (it was still under warranty) but the problem remained the same. all i could find on the internet is it may be related to a combination of wayland and KDE plasma iirc. i deactivated stuff recommended by users and tried other suggestions but nothing ever resolved the issue. i have a feeling it has to do with certain updates after which the issue ebbs and flows but this might just be because the problem only occurs randomly in the first place, so this is an entirely “vibes based observation”. my issue is definitely not an out of memory issue as i had btop open when it crashed and it showed memory usage of ~60%.