I’ve found it best to avoid the pacman repo. It can leave my system in such a weird inbetween state. Seeing as you mostly want codecs I tend to prefer flatpaks for VLC, Firefox, etc.
If you insist on pacman, just wait. If you try to dup and have a conflict it means that either pacman or suse repos aren’t all updated so hold on a few days and you should be able to dup with no issues.
Nope, it seems to just work!