@wogan 

Hi, welcome to the community.

Did most of the mobile devices behave like this:

"if a mobile device connects to the Deco it then will  not reconnect to any Omada APs without deleting the SSID credentials and re-entering (the same password)."

If we set different SSIDs for Deco and EAP, will it connect to the SSID of EAP when it is far away from Deco?

Or are you able to manually switch the 2 SSIDs without deleting the SSID credentials and re-entering (the same password)?

Wait for your reply and best regards.