Two questions :

1. I do have a "BT Smart Hub" as main router with Dual Next generation AC wi-fi :

I did follow the instructions to set up the tp-link AC2600 RE650.

I managed to connect to the 5GHz (solid blue line), but it does not manage to connect to the 2.4GHz (I tried several options).

I can connect some devices to the extender, and this is working fine, so it "does the job" (the main pupose was to connect my SMART TV to the extender for streaming)

But why is there an issue, is this an issue, and does it affect the overall performance in the house?

2. Just for my information, what's the basic principles of the extender :

- all the devices in the house "pick up" automatically the best connection depending on where they are in the house between the rooter and the extender?

- can the wifi extension affect the perfomance for the devices connected to the main router

Thanks