In the LXC (run commands as root user)

1. Create the group "lxc_shares" with GID=10000 in the LXC which will match the GID=110000 on the PVE host.

   groupadd -g 10000 lxc_shares

2. Add the user(s) that need access to the CIFS share to the group "lxc_shares". f.e.: jellyfin, plex, ... (the username depends on the application)

   usermod -aG lxc_shares USERNAME