Whose your provider? I have AT&T and have three AirTies SmartMesh 4920s extending the range of my Pace 5268AC modem. Having tried everything over the years, including access points and double routers, this finally works very well to provide a stable WiFi over a very long house. But as @steve.maddigan said, these are all wired to my cat8 LAN to provide a back haul to the modem. They auto transfer clients based on strength. They may auto switch frequency, but I don't remember. Honestly though, I try to get everything I can off WiFi and on wired ethernet if I can, because even the best WiFi isn't as good as ethernet.