@Eg64 before you downgrade, take a backup of the controller and export running log, you can find this under global and Maintenance at the very bottom. as you can see, I had somewhat similar problems,...

@Al-Mashriq you have an insanely large network, I would set the nettmask to 255.255.255.0 (172.16.1.0 255.255.255.0) you should set the lease time to 8 hours max.

@Alfred_A you can only use the Omada access point. Here are compatible APs https://www.tp-link.com/en/business-networking/omada/wifi/

@Pas7o i'm not sure how to do it, you almost have to look in the documentation of Omada and try. I would probably use vlan and not mac authentication, for example vlan 1 access points and switches...

@Pas7o buy a switch and you can configure port profiles.

@Al-Mashriq It seems that you are running out of IP addresses. what is the subnet mask on your network? how big is the dhcp pool? do you get internet if you set a fixed ip on your pc?