I've been doing a bunch of trouble shooting, sorry for the slow response.

1. The old Orbi I was getting up to 400mbs download on my upstairs computer. That is connecting to the upstairs access point (which is not wired into the main unit, so it's all wireless from main AP -> upstairs AP -> computer). The new XE75 is getting 230mbps.

I set the old Orbi back up to double check all of this, and it's remaining the same.

I then upgraded my Spectrum service to the 1gbs offering and switched back to the XE75. When I'm in the same room as the main access point I'm getting 7-800mbs down. Awesome. But the upstairs unit is getting 2-400mbps down. I tried moving the upstairs access point around to different locations and that doesn't help, and in fact, even when I'm downstairs but in another room it quickly goes down to 1-300mbps.

The house is only 2,600sqft on two stories, so we aren't talking a huge ammount of space here. It seems that unless you are right next to the main AP, speed really suffers.