I did the zero-log cleaning with the chat support of the #linux and btrfs channnels, thank you very much!!!
Now I rolled back before the last 2 stable updates, re-did those in one step and made the pacnew recommendations in the 23.07-10 thread. (https://forum.manjaro.org/t/stable-update-2023-07-10-kernels-plasma-gnome-libreoffice-pipewire-mozilla-wine/)
I deleted ALL snapshots after that roll-back date thru the Timeshift gui (that I suspected borked up the filesystem) although I
btrfs check /dev/mapper/ROOT
it (from live system) and it showed fine (Swap does not work with that check).
After this I did not have no system hangs at all anymore. The system shows fine, I had not rolled back far enough last time.
If no hangs occur I will mark this thread solved in a few days. Boot menu seems to list the snapshots fine.
Hope that some people can resort here to solve an issue like this with the info provided above in the future.
Btw, I will keep the baloo file search off.