@StefanoBau Is it possible your Satellites are too far from each other? Do this test: place both Satellites in same room with unobstructed view of each other, see if they follow connection preference...

@AzaNZ Neither one of new routers is going to join Deco mesh. You can have same SSID, but it is like deploying two independent WiFi routers with same SSID. You can google to find why having two...

@Kirkybaby When you are adding Satellite Deco to your Deco mesh, it must be able to communicate with Main Deco. Bring new M5 to the room where Main Deco is, power M5 on, do not connect it by Ethernet...

@Shigeru_Lloyd In theory, if Satellite Deco can't connect to Main Deco, it'll try to connect to another Satellite Deco. I wonder if something is up with new M4 you bought. Try this: 1. Place 'new' M4...

@Napalmo0 This switch should be compatible. Reminder: your setup will only work with Deco in Access Point mode, I would suggest connecting Satellite Deco to the switch only after you configured Deco...

@Vassilis Set password for Guest Network exactly the same as it is for Main Network. If Redmi won't connect to Guest Network after that, take careful look at password and special symbols in it. Start...