mesh Mesh advice for difficult home

[devster31]

Hello all,

I'm looking for WiFi coverage in my house which seems difficult.

Current equipment is a mess, here a small diagram, blue lines are top floor, green lines are bottom floor.

Because of various laws and the way the house was built I can't run wires outside or inside walls, so wired options would be strictly limited to powerline (which isn't great).

Currently WiFi doesn't go more than 2 walls, so I believe the best option would be some kind of mesh, possibly with powerline backhaul or dedicated radio backhaul.

I currently have 2 networks SSIDs + 1 guest and I'd like to unify them with this upgrade.

I was looking at TP-Link Deco line, Asus AirMesh equipment, something from Ubiquiti (which seems slower and mostly requiring cables), and finally some AmpliFi stuff.
Did I miss anything? What would you recommend as the best option for upgrades?

 

P.S. I'm EU based, so some equipment may be prohibitively expensive or very hard to get here.