CyberPunk2302thank you bro
This is Rog Phone 1 forum. Nevertheless, I have no issues connecting to my 5Ghz WiFi in ROG Phone 1 and hence should work of Rog Phone 2.
I would check the below one by one:
Ensure it has a different SSID - I mean different Wireless name for 2.4 and 5.
Try Changing the wifi channel number, keep trying different ones and check if it connects.
Try to change the wireless security type and see if it works.