Using different wifi access point

My question if I wanted to use the Deco as a modem and put the Telus modem into bridge mode, do the other 3 ports on the Telus modem stop working?

- No, the other three ports keep working as they always did, with the Telus Router completing all routing functions for those 3 ports

So whatever I put into those ports would have to now get plugged into another switch?

-Yes, if you want those devices on the same network as is whatever you connected to the bridged port.

Or is it better just to use the Deco as a wifi access point?

- Since you seem to get very good coverage, that is one option.

If I do that and unplug the wifi boosters, is there a way to have devices not connect to the built in wifi of the Telus modem itself and connect to the Deco access points.

- Yes. Have each device 'Forget' the current network, and then connect each to the SSID of the new network.