You can make another support thread to ask for help with this. Hiccups sometimes happen, and Manjaro was intentionally designed to not try to be 100% stable in order to deliver updates much faster.
Also, you shouldn’t expect to get your save data back (e.g. browsing history) when using a repository version of a program after having used the flatpak version, since they are stored in different places. You will need to perform additional steps to transfer the data, depending on the program.
Before I end this thread here, I’d like to report back to all those, who’re reading and maybe benefiting from the info, contanined within these corresponding posts, as much as I did that
I’ve got my operating system back, working even better than before
Did a major cleanup that I wouldn’t even know how, otherwise.
Eliminated future source of possible concerns, instabilities or problems by resolving issues with AUR/snap packages and reduced flatpaks down to 3 apps.
By following fasto’s recommendations (uninstalling all flatpak apps, and deleting its root directory and then reinstalling only the ones I needed that were not available in the official repositories), I regained 16GB of disk space.
One flatpak app that I had to replace with, from the official repositories, that was not launching and working at first, is now working with a simply solution due to fasto’s recommendation.
fasto, cscs and brahma, thank you once again. And hope to meet you again in another post!