votdev Not a nightmare but sometimes things do not work due to old adjustments.
Francobritannique Did you ever touch the etc/nsmb.conf file on your Mac in the past?! If so, maybe copy its content, save it somewhere as a text file for later and then delete it. Reboot. Reconnect the samba shares.
macOS requires SMB 3 protocol strictly and if you changed that file in the past it might be the culprit.