@MVLRM 

Deco 3,4,5 will still try to connect to Main Deco, but if you can wire Deco 2 it could be made Main. The process depends on how you run your run Deco mesh: in Router or in Access Point mode. Can you clarify that?

Also, if in Router mode, can you switch Deco mesh to Access Point mode instead?

  @MVLRM 

You've got two conflicting opinions, but they are from the same solution. You need to wire Deco 2 to Main Deco.

Bounce Decos 3,4,5 and if they reconnect to wired Deco 2 you are all set. If not, I can give you steps to make Deco 2 your new Main Deco. The process of changing Main Deco is seamless for Deco mesh running in Access Point mode, but there is a trick if you need to run Deco mesh in Router mode, for your specific setup. The good news: it should work.