My house is made of two main floors from big tuff walls, i.e. low penetration on 5GHz and acceptable signal on 2.4Ghz, mainly trought the floors.
My current setup features two accesss point at 2.4 Ghz, with the same bssid on distant channels (1-13), one of witch is the provider's router, the other is a Tp-link wd2543 run by openwrt in AP mode.
I would setup a 802.11s mesh network open-wrt based, so I'm wondering which devices would work best.
A dual band AP would be useful for near clients, but widespread network should be 2.4Ghz based.
I'm considering 8/64MB repeaters, such as tp-link re450 (wich seems not yet supported in the lastest v3 version) or cheap d-link dap-1330.
The backbone could be wired ethernet.
This makes it rather simple, in that case you don't need 'mesh' at all (your clients don't understand it anyways), but simply set up your routers as dumb-APs. If you want to optimize roaming and handover, look at 802.11k/v/r, but these are optional.