Bumping the thread, really would like to know if I need to return this router.

@KernelHappy 

First, let me say, I do not have that router.

I would try it with Smart Connect and QoS off, Use separate named SSIDs. 

A good 'white paper' on WIFI for other info https://www.duckware.com/tech/wifi-in-the-us.html

@ArcherC8 

Thank you for the suggestions. 

My primary concern is not the wireless, it's that the AX90 is slower wired than the FiOS quantum router.  Using a wired connection I'm short almost 200mbps on the upstream on the WAN port, while downstream seems comparable.  Wireless settings should not effect the wired connectivity. 

I already have QoS disabled but thank you for the tip on smart connect, usually the first thing I do is assign different SSIDs so I can troubleshoot and I through tplink disabled that ability completely, didn't realize smart connect was masking it. 

Regarding wireless performance;  I don't know that I actually have a problem or If maybe I'm running into some sort of bandwidth shaping being done by the AX90.  Using the speedtest.net windows app, over the course of a relatively short speed test, I seem to be down in the 200-300mbps up/down however; 

When transferring large files from a wireless PC to a wired PC using windows file sharing, I'm getting 60-70MBy/sec which equates to 560mbit which is excellent considering there are several devices streaming video at the same time and, the wireless PC is on another floor of the house.  It seems like the router might be prioritizing local network traffic or, the larger and longer duration file transfers are allowing the router more opportunity to optimize the connection.

I will also say that connectivity among devices seems more consistent and robust, I've been able to move several devices off a secondary WAP I had to put up for the edge of the house and, my son who was using the FiOS router in the same location as the AX90, has stopped complaining about his connectivity issues while gaming. 

TLDR; wireless seems ok, but the wired connectoin is still problematic