Hello @taffy63 , May I know what is the error message if Huawei P30 phone failed to connect to WiFi?
You could try to forget extender wifi on the phone and reconnect to extender (extender use the same wifi password as router)
Go to Settings-> WiFi on your phone, Tap (or Long press the router's WiFi name ->Forget / Delete the network
-May I know the model and hardware version of your tp-link device, you could check on the back label.
-If you delete router WiFi and reconnect to router WiFi signal, will phone work with router wifi?