YouHua WR1200JS speed issues / firmware

I have three of these units CAT6 hardwired, running as simple access points, both upstairs/downstairs. My hardwired speeds are fine on these devices (650/25). However, my WiFi speeds are pretty bad, at only 150-200Mbps. I'm fairly certain, it is a driver issue.

I've tried firmwares:

I used this script to convert the units into a 'DumbAP':

Both firmwares with the same results. Here is my wifi config:

config wifi-device 'radio1'
	option type 'mac80211'
	option path '1e140000.pcie/pci0000:00/0000:00:01.0/0000:02:00.0'
	option channel '44'
	option band '5g'
	option htmode 'VHT80'

config wifi-iface 'default_radio1'
	option device 'radio1'
	option network 'lan'
	option mode 'ap'
	option ssid 'sr_guy-5Ghz-Livingroom'
	option key 'Password
	option encryption 'psk2+ccmp'

I disabled wifi on two of the units, and ran a speed test from the third, to see if signal interference was the cause, but I had the same speed results.

Can anybody that has these units that doesn't have this problem point me to which firmware you are using? And if there are differences with your wireless config you are using?