@djrtnyc 

It's just a debugging technique.  My above posts are just to triage where the speed is reduced. Reversing all the steps one, by one, is advisable.  

@philipbi Ok, so I've got it all working now.  Results posted at the bottom.

BLUF:

I did two things differently this time around:

1. I did a reset to factory defaults via the GUI, instead of using the physical button on the back of the device.
2. I went into Advanced -> USB and disabled all that functionality (Specifically "Media Sharing").

And now I am getting 850mbps+ results on my Gigabit Network Adapters...consistently!

So then I started turning things back on that I wanted back on.  Everything is still working great.

My equipment:

XFinity 1.2 Gbps Plan -> RG-6 Cable -> Arris S33 Modem (2.5 Gbps port / DOCSIS 3.1) -> CAT 6 -> TP-Link AX11000 -> CAT 5e (to Master Bedroom jack) -> CAT 6 -> MSI GE75 Raider Laptop (1 Gbps port)

1. Advanced/Network/LAN : Uncheck Link Aggregation (Off)
2. Advanced/Network/IPTV/VLAN :  Uncheck IPTV (Off)
3. Advanced/NAT/UPnP: (On)
4. Advanced/NAT/DMZ:  (Off)
5. Advanced/HomeCare/Parent Controls: remove any Parent entries (Off)
6. Advanced/HomeCare: QoS: Click EDIT icon(paper/pencil) next to Total Bandwidth.  Set to 60 Up / 1400 Down (Confirmed) (I pay for 35 Up / 1200 Down)
7. Advanced/HomeCare/Antivirus:  Turned on all three Malicious Filter, Intrusion, Infection toggles. 
8. Advanced/Security/Firewall: SPI Firewall (On)
9. Advanced/Security/AccessControl: Toggle Off (Confirmed)
10. Advanced/Security/IP&MAC Binding: Toggle Off (Confirmed)
11. Advanced/IPv6: Toggle OFF (Confirmed)
12. Advanced/OneMesh: Turn OFF (Confirmed)
13. Advanced/USB: Off
14. I also plugged in all other network devices.
15. Enabled Wifi
16. Internet Port Negotiation Speed Setting: Auto Negotiate
17. And I agree, the router speed test is ridiculously unreliable.  You would think it would show faster speeds than the endpoint devices.

Thank you all again for all of your help and input.  I don't know if the changes I made really did the trick, or it was just a matter of rinse and repeat and success after the 50th time.  Who knows...

Final Results from SpeedTest.net (I pay for 1200 Down / 35 Up) and am running these tests off a gigabit ethernet port connection:

The Router Speed Test is still unreliale, but I'm not concerned about that:

@Ayato I am soooooooo happy for you. It feels good, doesn't it?!?!

@tp-link you need to WAKEUP and fix this, as you promised me you would. This is starting to be embarrassing.  This router is glitchy. throttles user' bandwidth without them knowing, and zero way to resolve it without hours and hours of consumer time, which we should bill you for, since we are now officially our Testers. 

Fix the Performance lags.

Fix the Speedtest.net API so it doesn't lie to us. Even though this isn't your api, it is making TP-Link look less credible. 

@KIdneykids same with Fios. Locked at 850/850. I had frontier  come out and it's 100% the TP link router. There's got 990/1050

  @Mistfitswitch 

Exactly the issue I had.

Got my full bandwidth w/ ALL my old routers. 100% u/d but the brand new ax11000 uploads got tanked and my speeds, especially upload were totally laughable.

FTR, seems like tp-link solutions keep asking users to jump through hoops while the "solutions" are people settling or only have plans where the heavy bandwidth is on the DL side. So far it seems like most of the "unsolved" users have heavy bandwidth on both sides.

But what's the sense of spending all that money for something where the solution is asking you to remote in, spend hours troubleshooting and turn off half the settings you wanted by purchasing this router only to get close to the bandwidth you're paying for then have a thread get marked as "solved" w/a solution that is for another router for an issue that's over a year old now.