@dills Do you have channel options set to AUTO? I had a similar issue and manually set my channel and channel width and got the results I expected. Might not be your issue but it is simple starting point.

  @RickJamesBish Thanks for the suggestion! I've gone down the rabbit hole on this and ended up solving the LAN issues by changing the frame size on my NAS. I now get gigabit speeds within the wireless LAN. However, I'm still getting slow upload speeds over WAN which is stange. Within the LAN I get sustained 800/800mbps within line of sight of the AP. Over WAN it's more like 700/300 even though my wired connection is gigabit.

To troubleshoot I've removed the ER605 from the equation and replaced it with an ASUS routers.... Same Results.

I also tried putting the EAP670 into standalone AP mode with my Asus router... Same Results.

What's odd is that my old Asus (RT-AX89X) router achieves faster wireless speeds at around 700mbps up and 700mbps down with the EXACT same settings including the same channel width and channel selections!

Really scratching my head here. I like the Omada system but if I can't get this to work I might just go back to my old Asus system.

  @dills What do you get on different speed tests, say openspeedtest.com and/or fast.com?  I personally stopped using speedtest.net due to odd consistency a long time ago.  If you are seeing 800/800 internally from WiFi (did you use iperf or something else?) and your internet is also capable of those speeds, you should be seeing those via WAN as well.  The fact that you aren't would lead me down a long list of tests, most of which you've probably already accomplished.  I would try some other external speed test sites, like the ones I listed above, and see what I get from them.

  @Vilmalith Just ran a handful of tests on various sites. It's pretty consistent that I get 600-850 down and around 250-300 up. I've tried just about every setting in the book from Airtime fairness, channel selection, channel width, swapping cables, etc... What's odd is that within my LAN when I transfer files I get symmetric 800/800+ up and down upload is only limited over WAN... But if I plug directly into the ER605 router I get full gigabit up and down speeds.... so it appears to be something with WIFI on the EAP670?! When I swap out all of this hardware for my old Asus RT-AX89X I get much faster upload speeds. Super confusing!

  @dills I know there is something going on that does not necessarily pertain to this comment, but I do not trust any of those sites. Main reason is we just intalled Gigabit on the RV Park so 1000/1000 down up. They are only delivery about 580 down testing wired at the modem.  At my camper, with the following topology, My PC _My Router_CPE710----EAP610 Outdoor_Switch_Router_Modem,  SpeedTest shows it maxing at about 315mbps however I did file download and got 69MB/s, which is roughly 578Mbps, which is practically every bit of bandwidth we are getting.

But like I said, not really anything to do with your situation but these speedtest to me are not reliable.