Avast's Firewall should automatically allow/whitelist inbound connection for "WsaClient.exe".
It requires for running Android apps on Windows 11. Firewall in Public mode blocks it.
Avast doesn't seem to have an option like Windows Firewall to notify when an inbound connection is blocked. Otherwise, it wouldn't be much of an issue. Since it doesn't have, it will become a problem for average users who want to use Android apps to understand why their Windows Subsystem for Android is not working. Avast Free also have Firewall, so the number of users who may face this issue is large.
If Avast internally whitelists this item, then it'll probably be the best solution. Any other better solution will be welcome too, of course.