CAX80 mesh setup

Hi - my home is over 3000 sq. with dedicated coax line from outside of the house to my attic and into my office.  There is Cat5e all thru the house a patch panel downstairs but based on various decisions while we have lived at the house left most of the ports alone.

I recently upgraded my bandwidth and now have a CAX80 on the 2nd floor in my office which has an open view to the downstairs.  Master BD is on the 1st floor and have a few devices that connect at various times.  Looking to boost my signal without having to drop a line or using multiple \ additional SSID's.  I think I am looking to mesh my network and put the device in an open area downstairs that is close to the master bd.

My ISP is Xfinity and plan is at 1.2Gb.  I am broadcasting both wireless channels with 5 GHz hidden.

I called the product support sales phone number, and they recommended the EX80 (AX600) and the EX7000 along with the EX7300.  There were other recommendations, but I was unable to write them all down.  I had a tplink that will not take the configuration and recently purchased a range extender that requires me to create its' own ssid which is what I am trying to avoid.  Your help and recommendations are most appreciated.

SDL_Sports_Photography