I have an Archer AX11000 v1 hardware and the latest firmware: 1.3.2 Build 20221128 rel.45807(5553)

My ISP recently rolled out 1.2Gbps Download; 40Mbps Upload from my local cable provider. 

Previously I was on 600Mbps download; 20Mbps upload
Internet Speed test performed on the AX11000 via http://tplinkwifi.net/ consistently shows between 500Mbps and 580Mbps download and 40Mbps upload.

The download speed is slightly higher than I was getting before upgrading my speed but less than 50Mbps improvement

The Modem is DOCSIS Version 3.1

ISP came out and tested everything. Directly wired into the modem is getting 850Mbps to 900Mbps download.

I have tried testing with QoS off and with QoS on Standard with manual values for the Total Bandwidth. Neither impacts the speed.

I have IPv6 turned on

OneMesh is off

I do have SmartConnect on and have not tested with it off (based on the forum posts here that does not typically fix this issue)

I do have a USB storage device attached but I'm not sure how that would be impacting overall speed.

Wireless devices less than 3 feet from the router are getting 400-450 Mbps. Given that there are ~50 devices on the network, I understand the loss wirelessly. 

But it should be higher.

I have seen a lot of posts on this forum from product owners that have upgraded to 1GB service and aren't getting close to that. I'd be excited with 750-850Mbps honestly. 

Is this a problem that can be fixed or should I look for a new router; different brand?

Thanks

rs