I just bought the Deco x90 to replace my old early Orbi WiFi 5 mesh   I have 1 gigabyte download and 500 mps upload from my ISP.    I was thinking about upgrading to 1.5 gigabyte download 500upload or 1 gigabyte down and 1 gigabytes up. .    I see potential bottlenecks with the  it having only one 2.5 gigabyte port and the other being 1 gigabyte...... I am assuming that it is not possible to achieve higher then 1 gigabyte on WiFi 6 even if using wired backhaul so I would connect the 2.5 gigabyte port to my ISP then the other port is only 1 gigabyte so whatever I wire into that port will be capped at 1 gigabyte   My pc, or another x90 or anything else would not get 1.5 gigabytes from my isp, even if I added a multi gigabyte switch, etc.  am I wrong in my assumption? 
 

now I will talk about my current setup.  I am in a 3 story townhouse using the 2nd 5G band as backhaul  first Deco main unit is on the first floor.  I get up to 800 mps on WiFi. I am I impressed. My old Orbi setup maxed out around 300 mbs. On WiFi.  3rd floor I have 2nd deco.  It was a challenge to find the spots with best coverage .... I am getting speeds up to 500 mps on the second x90. My old Orbi did 300 mps on the Satellite as well.     I couldn't keep the x 90 in the same spot as my old Orbi system.  Both x 90 units I put near windows so the signal doesn't have to travel through all the walls but it does sacrifice the 2nd floor a bit.  The signal is shows\ 3 bars connected to main deco so assuming I can't get any better.

Now to my point mentioned above.   I know I couldn't achieve 1.5 gigabytes on my 2nd Deco but I don't think it could be done on the main one either because of that 1 gigabyte port.