In very condition, dual setup mesh MX5300 routers from Linksys. Comes with power adapters.
The MX5300 has good specs for a WiFi 6 router:
- Qualcomm IPQ8072A with 4 cores at 2.2 GHz
- 1 GB of RAM
- 512 MB of NAND flash
It's also fully supported by OpenWRT.