Just wanted to share this experience with the community because I suspect others may be going through the same thing.

We've got a gigabit up/down fiber connection. Our AX11000 (hardware v1.6) just can't deliver the full speed. Even the onboard speed tests rarely crack 900MB down or up. It's not the fiber connection because speeds are usually 900MB+ when directly connected to the modem via ethernet. I realize that you can't expect the full gigabit speeds when connected to the router (or even directly to the modem), but our test results weren't even close and they were always strong when connected directly to the modem.

We went through extensive debugging with TP-Link support for a month before we all agreed that the AX11000 just couldn't deliver the full gigabit speeds. They were going to swap it with another AX11000 but I think they decided it was unlikely to solve the problem so they offered up a Deco X90 instead. We're waiting for that to be delivered. I'll update this post with the results.

During the testing, we found that both the wireless and the wired speeds on the router were really unreliable and never delivered the full gigabit speeds. In many tests, the wired connection was actually slower than the wireless connection. We were testing using Wifi 6 right next to the router. We tested multiple ports on the router and all three wifi bands - nothing delivered consistently acceptable results.

During the process, I must have run over 100 tests and we tried some beta firmware (that was numerically older than the public firmware). Tech support, which was actually really good during this process, setup a remote session and ran speed tests from the CLI on the router and those weren't up to snuff, either.

I would love to hear if anyone else with an AX11000 had a similar experience and if they ever found a solution. Did you get a Dec X90, and did that help? Did you end up going a different route altogether?