I run PhpStorm 2023.1 on Windows 11. On the Windows machine, I have an Ubuntu WSL enabled, so that I can develop a PHP project, which works fine.
Now I wanted to enable PHPStan support yet I get the error:
phpstan: 'php' is not recognized as an internal or external command, operable program or batch file.
In the PHPStan settings within PhpStorm I have added the WSL config, and it validates:

I wanted to remove the System PHP config, yet the option is greyed out:

How to enable PHPStan support here?
What do you have for PHPStan at:
Settings/Preferences | PHP | Quality Tools | PHPStan?Have you tried selecting the correct PHP interpreter there?
If you did and that still does not work then please do the following: make sure that this "Ubuntu-22.04" PHP interpreter is selected as default for this project and then use:
By default project interpreterin PHPStan config at the aforementioned place.Regarding System PHP removal. It is not possible to do that right now (latest stable PhpStorm 2023.2.3 version).
Watch for issues WI-70523 and/or WI-56550 tickets (star/vote/comment) to get notified with any progress.