If you dont mind, I can sell you mine, Mercusys H70x, bought it for 399 during 12.12 sales, retail price around 450.

But if your subscription speed is more than 300mbps, I wouldn't suggest you to use it as I'm facing problem for speeds over 300mbps

TP-Link Deco mesh. Best value for me + idiot proof set up (I set up as AP mode)

Got my X50-POE & super happy with it (only 1 unit as apartment only 1,400 sq ft)

Since yours is 3 stories house, (if can afford it) go for tri-band mesh like BE-85 , XE-75 (both models sells 3 pack). Tri-band better as the third band is separated out for comms with the other mesh unit, leaving the other 2 bands to serve you.

https://www.tp-link.com/my/home-networking/deco/