In that respect, SMB has improved since OMV 2.x (still not as good as AFP but's marginal now)
Situation with macOS SMB clients is special and the challenges are outlined a bit here. Asides that check 'ok-ish' setup scores with pretty recent Samba and appropriate smb.conf settings there: https://github.com/openmediava…01#issuecomment-468270197