Try smart umount as a simple solution (no credentials needed).

roles/lmn_printer/tasks/main.yml

@@ -30,7 +30,8 @@
         path="sysvol/"
         mountpoint="/srv/samba/%(USER)/sysvol"
         options="sec=krb5i,cruid=%(USERUID),user=%(USER),gid=1010,file_mode=0770,dir_mode=0770,mfsymlinks"
-      ><not><or><user>root</user><user>ansible</user><user>Debian-gdm</user><user>sddm</user><user>virti</user></or></not></volume>
+        ><not><or><user>root</user><user>ansible</user><user>Debian-gdm</user><user>sddm</user><user>virti</user></or></not>
+      </volume>
     insertafter: "<!-- Volume definitions -->"
 
 - name: Create /etc/linuxmuster-linuxclient7 Directory