There is a difference between standard Wifi booster/repeater and those of them that can extend the network seamlessly. Read the linked post. My older TPLink repeater acted as what Darell wrote above - more interference, dropouts of Zwift and work calls. I switched it for a newer TPLink repeater with OneMesh feature and since then no more drops ever.
There may indeed be interference in the 2.4 GHz spectrum where both Wifi and BT run. Some channels can also be used by others if you are living in apartment area. Changing to 5 GHz can help but remember that it has smaller range than 2.4 GHz.