@gg_pt >"DECO is working well" That could mean no devices are connected to this particular Deco.

@Mark_Deco-M9v.2 >i removed every other deco from the network (unplugged - left only main one in use - no difference) Have you tried this with Main Deco in Access Point mode?

@DinghyDog Also, here is comparison between sizes of M9 and M5 power adapters. M9 is on top.

@NeilF >Can you still create a Guest Network in AP mode Yes, you can - but it does not mean what we think it should mean. Devices on Guest Network in AP can see and can access Main Network. There is...

@AbulaBula X20 supports WiFi6. Out of all Deco models only two support WiFi6 currently: X20 and X60. Your best bet will be to buy one or more Deco X20 to create a mesh.

@brooklyn27 I think you are overcomplicating things. Some of TP Link FAQ articles are not very clear, but even then I am not sure how you deducted from one you referred to that you'll need separate...