I actually have a EAP673(EU) v1.0 but it seems to not be available in the 'model' dropdown, and does seem to be running the same firmware as the 670v2. 

The 2 access points I have are both running the latest firmware available 1.0.15 for the 650, and 1.0.4 for the 673.   I've tried the obligatory speedtests multiple times, and also iperf tests from my M1 Macbook Pro (Max) which I know only supports Wifi6 with 80hz, but also from my PC and iPhone 15 Pro Max which are full WIFI 6E on 160hz.  I've not got any special vlan's, and the access points are hardwired to my router via 1g ethernet.  No matter the access point I can only get about 300mbits/s.  My broadband is 500mbits/s but even with iperf (as seen below to the access point i'm connected to it's the same). 

// EAP673 (line of sight, 10 feet distance) Run 1:

➜ iperf -c 192.168.1.223
------------------------------------------------------------
Client connecting to 192.168.1.223, TCP port 5001
TCP window size:  128 KByte (default)
------------------------------------------------------------
[  1] local 192.168.1.65 port 57517 connected with 192.168.1.223 port 5001
[ ID] Interval       Transfer     Bandwidth
[  1] 0.00-10.04 sec   355 MBytes   297 Mbits/sec

➜ iperf -c 192.168.1.172
------------------------------------------------------------
Client connecting to 192.168.1.172, TCP port 5001
TCP window size:  128 KByte (default)
------------------------------------------------------------
[  1] local 192.168.1.65 port 56896 connected with 192.168.1.172 port 5001
[ ID] Interval       Transfer     Bandwidth
[  1] 0.00-10.11 sec   411 MBytes   341 Mbits/sec

// EAP673 run 2

➜ iperf -c 192.168.1.223
------------------------------------------------------------
Client connecting to 192.168.1.223, TCP port 5001
TCP window size:  128 KByte (default)
------------------------------------------------------------
[  1] local 192.168.1.65 port 61679 connected with 192.168.1.223 port 5001
[ ID] Interval       Transfer     Bandwidth
[  1] 0.00-10.18 sec   321 MBytes   264 Mbits/sec

I've tried the WLAN Optimization multiple times, and I've even tried playing with all the settings on the EAP673 device's wireless radio config manually.. Specifing manual channel width (160/80/40), channels (tried most of them manually), Power (high/med) etc. 

Also in the wireless networks for the organization, no rate limiting is enabled, i've only got "mesh" and "auto failover" eanbled in Site -> Wireless features

Nothing I do seems to make a difference.  The speeds are quite pathetic.  What am I missing?