The VLAN mode of CCTV switches is not like the VLANs of common manageable switches that support VLAN tagging.
When this mode is activated, what it does is to create a VLAN between each of the PoE ports of the switch and its uplinks (between port 1 and uplinks, between port 2 and uplinks, etc.) so that what is connected to port 1 has no communication with port 2, or 3, 4... and likewise port 2 does not communicate with port 1, 3, 4...
Its function is that if it is connected to one of the free PoE ports of the switch, it cannot access the cameras or devices connected to the rest of the ports, thus increasing its privacy and avoiding brute force attacks for its access.
It is not designed to size or compartmentalize networks like the VLANs of a conventional switch, nor does it allow you to change the VLAN they use to work with other existing VLANs on the network into which they may be incorporated.