I will be using two Custom firmware routers to get full house coverage on a very old house with thick lead filled walls. The entire project took 6 hours due to some unexpected issues we faced. You can flash any device below as well to Merlin custom firmware but its entirely optional. This will work with the stock firmware.
Very few people know that you can save yourself some money by buying a T-mobile router on Amazon. Downside is having to flash it to have the latest firmware free of vulnerabilities. In this guide I will show you how to flash a TM-AC1900 to a RT-AC68U then into merlin custom firmware. I have tested it myself and can confirm that it works.