@DecoUser123 After selecting "WiFi network and backhaul", did you also set up a password & security for that 6Ghz network? Full instructions here: How to Use the 6 GHz Band of Your Deco WiFi 6E...

@Tonmeister You need to set up connection preference on your Deco: How to select a preferred signal source on the Deco App (part 1)

@pibew84514 You don't need "reasons" to go from M4 to XE75. Do it if possible

@tc323 That looks like either a custom firmware or a very old one. If it is a custom firmware, contact your ISP

@Hispanico That would be adding another Deco to a new network, not to your existing one afaik. If you have another router for "another AP" that you mentioned, then set it up using the app

@rantsa No way to know this