Orbi or Nighthawk? I have CAX30 AX2700.

I have gigabit service with Xfinity.  My CAX30 does well in my living room, but seriously degrades in my adjacent bedroom and is practically non-existent in my office on the second floor.  Will add-on mesh extenders on the CAX30 extend a strong signal or will it cut it in half (as I’ve read somewhere).  Or, should I return the Nighthawk and buy an Orbi mesh system?  Or is there an option that I haven’t explored?

I had an older Eero router system (base with two remotes) with a Motorola modem.  This worked well for years, but the Eero started cutting off and was very hot to the touch. I am frequently in another city and can reboot the modem, but not the Eero router.  That is why I have been thinking of the modem/router combination.

I don’t play games, but I use it for streaming 2 tvs, and about 15 or so other devices (lights, thermostat, garage door, sprinkler, etc.).

This is so confusing to me, so I hope someone can give me a great solution.  Thank you in advance.

Rick, Lewes, DE