@Ensio
Hi, if Vivaldi do this for all users nobody would use it.
Vivaldi never freeze and rarely crash for me, maybe a few times a Year.
The most crash reports are OOM (Out of Memory), this can caused by extensions and/or 1000+ tabs open.
The others are often broken user profiles, a crash can corrupt the user profile for example.
Create a second user Profile, don't change or install anything and test there.
If you can reproduce it there you can report it to the bug tracker with added crash logs.
Cheers, mib