@SpiDybot 

Hi,

This may not be what you'd like to hear, but getting a speed of 200 Mbps through one wall (i.e. room next door) and one RE700X wireless range extender sounds quite reasonable.

Every wall attenuates the wireless signal substantially (which in turn results in less speed) and a wireless range extender further reduces data throughput due to the way they work. 

For explanation: These simple range extenders "repeat" the wireless signal on the same frequency (i.e. channel) that is also used by the host wireless network. Basically, one frequency is being utilized twice to transfer the data from the AX6000 via the RE700X to the Wi-Fi adapter of your laptop.

By the way, the fact that the AX6000 only supports OneMesh, but no EasyMesh, does not matter in this case.

  @woozle 

Thank you!

I'm aware of the loss principle but honestly expected these rather new designs to work better.

https://www.tp-link.com/dk/home-networking/range-extender/re700x/

My previous house was wired but my aim is to now avoid the mess of running cables by setting up these RE700's. Specifically on a star topology (as opposed to daisychain).

The data flow is stable, speed not as expected. Taking your word into consideration I might consider loft wiring if better speed is needed.

BTW the TP app "Tether" suggests putting the RE700's further away from the router!