Dual-device mesh using dedicated router for backhaul

After trying a few different wireless mesh devices, I am disappointed in the stock firmware. The Google devices are only AC1200 dual-band and require you to enable cloud-functionality for basic features like device management, reservations, and port forwarding. The TP-Link Deco devices I bought requires an online account that shares the password with your device and they have a very concerning privacy policy. Both of these require a mobile app for configuration. I tried a NETGEAR mesh network pack, but unfortunately it had its own issues as well. It at least seemed better in terms of privacy and had a web interface.

All of these devices average around $200–300 for 3 or 4 devices. I really miss OpenWrt and would like to find out a solution that works to give me around the same performance as a tri-band mesh setup. I saw an interesting post that got me thinking. What if I purchased 6 dual-band routers, two-for each room. Would it be possible to use one as a dedicated wireless backhaul, connected to the second device in each room via ethernet. Then that way my WiFi devices connect to the the non-backhaul router. Would this setup still support things like fast roaming or something similar to automatically switch routers depending on what room I'm in?

I can find some descent AC1750 devices that support OpenWrt for around $50. It may be a little more expensive, but seems like it would be worth it if this works. I imagine that backhaul may be better since I could potentially use both bands simultaneously for the backhaul. The other concern is just managing this many devices, but I would think if they are all the same it should be pretty easy to automate. Does anyone have any experience using a configuration like this? I did find another tri-band device today made by ASUS for around $100 that I might try if this isn't feasible, but I'd really prefer to use OpenWrt.

Technically, yes… But it's power-hungry, expensive and ugly to manage.

There are a couple of tri-radio devices supported by OpenWrt, in particular the ipq4019 based ones (802.11ac/ wave2, 2x2:2), https://openwrt.org/tag/3wnic?do=showtag&tag=3wnic