I been experiencing the same issue, if you go to Settings/ your Icloud name/ICloud/ Private Relay and turn it off this will fix the issue with Alexa App not having internet.
I notice as well that the following Apps not working correctly on Private Relay:
Unifi Network App
OKTA verification App
HotSpot (your devices from the phone)
Tesla App
iRobot App (was not working on 5G but on LTE was working now they fixed it)