Setting up Wifi 6

I purchased a Nighthawk AX8 to replace my Orbi 5 system. My goal was to start adding Wifi 6 equipment as it is available.  Although the Nighthawk has pretty good coverage, my house is about 3,000 sq ft and my office is in the opposite side of the house, 3 floors up.  I can still get a 5ghz connection, but it is very weak.  I am considering purchasing a Nighthawk EAX80 Range Extender that also has Wifi 6 (Mesh Network).  

I have two questions.

1. I assume I will not have to have a hard wire on the extender

• Since it is not an access point (its a mesh network), I should not lose bandwidth (splitting bandwidth in 1/2)?

My goal is to have a full 5ghz connection throughout the house.  At this time, I am not considering running more wire in the house. I would like to keeps it mostly wireless.