if you want just plugin your tplink routers into spare port on your deco your router should work on your deco network with no issues I did the same with my ax73 with ex75pro deco everything works fine

  @LoryLory_IT 

What do you mean by "satellite"?  Why do you want to use the Deco as a satellite?

If you change the mode of the Deco in AP mode, it will let the main router handle tasks such as assigning IP addresses to the device.

Regardless of the mode, the Deco will not participate in another mesh.

  @LoryLory_IT I am facing same issue by using my mobile apllication