@K9Texas TX Link web pages says you can in fact use ONE MESH to wirelessly connect the routers to extend coverage however it did not work. That is what is frustration. Having a manifacturer say you can use One Mesh and then having THEIR routers not connecting.  Huffff

  @Riley_S  OK, I have just sucessfully linked TWO Tp-Link routers by Wi-Fi. I am an old retired person so for me to be able to succesfully do it is in and of itself a miracle. Here is the solution....... I purchased another TP-Link router (Same model as my primary router). Specifically, the Ax3000 (Archer AX55). My main router is the Archer AX55-PRO, but basically the same unit. I followed the instructions, updated firmware on both units and using the youtube video titled ..... HOW TO SET UP ARCHER AX55 WITH EASYMESH MESH WI-FI .... I was able to connect link both units. Now I have 300gbps in the study where before the speed was 40gbps. 

I THINK, and again, I am NO tech savy person, the reason they linked is because both units are the same model, where as trying to link the AX1800 did not work. I got the 2nd unit on Amazon at a huge discount for Prime day so it was basically cheaper than TP's high end range extender. 

I sincerely hope this information helps others trying to do the same thing. The ONE great advantage to buying a 2nd router is now I have a backup if for some reason the primary dies. 

Have A BLESSED DAY EVERYONE !