After stringing together various free extensions for vscode that didn't quite do the job, I came across PHP Tools. I removed the free extensions and installed PHP Tools, and signed up for a trial license to see what it's like before buying a full license.
Unfortunately, it doesn't appear to be installed correctly - or is the 30-day trial severely cut down?
For example, the PHPUnit tests do not appear in the test explorer, and even the basic IntelliSense is limited.
The PHP log says the extension has started.
PHP Tools extension started.
Found PHP, version: 8.0.3, Xdebug: 3.0.4.
Info: Requiring additional package on macOS.
PHP language server started.
As well as the PHP language server.
PHP Tools server started.
Path: /Users/Gav/.vscode/extensions/devsense.phptools-vscode-1.2.6549/out/server/Devsense.PHP.LanguageServer.dll
PID: 66004
Processing files: .php; .php5`