I will test this. Thank you for suggestion.It looks like you run into the QTBUG-7884 despite (or due to) the https://github.com/obsproject/obs-studio/pull/7589
Try to disable Show pixel alignment guides option in OBS Settings>General
The only plugin/add-on that I use is Animated Lower Thirds with Dockable Control Panel. When I wrote the post I didn't know that was a newer version.The most probably cause of this crash is a plugin that needs to be updated or removed.
Also, 29.1.1 is latest versions.