GCC12 preventing update

To solve your issue with updating - yes

The manjaro related packages is obsolete and has been removed from repo - you don’t need any of them.

If there is something you really must have - make a note and rebuild them after a succesful sync.

To remove them

sudo pacman -R $(pacman -Qqm)

Then run a full system sync

sudo pacman -Syu

Please note that building custom scripts using AUR implies using as a minimum Manjaro testing branch.