soniktrooth I can't seem to run a Drupal site without explicitly providing the port number
If you're experiencing this even when there are no other PHP applications in your stack, then I now believe this issue is indeed different, so yes please, do create a new issue for that one.
Regarding the main theme of this issue (problems with multiple Drupal sites), my research thus far is indicating that the cause is the shared PHP service.
A quick way to work around it for now is to NOT share a PHP service between the sites, but rather to add multiple PHP services, even if they are the same version. So for example, to run two Drupal 10 sites, add two PHP 8.2 services, and power the first Drupal site using one PHP and the other Drupal site using the other PHP.
Let me know how you get on!