What's the IP of the system running Omada Controller? What's the IP of the router? Why is your default gateway in another subnet than the EAP?

In our country low voltage is AC voltage up to 1,000 volts and DC voltage up to 1,500 volts. You probably mean extra low voltage (ELV), which is AC voltage up to 50 volts and DC voltage up to 120...

One problem with exchanging antennas is the EIRP - make sure you don't violate the max. EIRP (not a technical issue, but a legal issue). I don't know what beam width your yagi antennas have, but even...

Could be caused by interferences. Things you can try: Select 20 MHz channel width. Set 802.11n-only mode. Use another channel (make a WLAN survey to find out best channel).

Just below the post, on the left of the Reply button, but disappears if one has been selected, re-appears if one is unselected.

I think you can add a Free Authentication Policy to allow access for certain devices without authentication, but I never did test it. On the other hand you could also add a second WLAN/SSID without...