I've noticed that Visual Studio 2019 is hanging quite regularly for a few seconds when editing PHP files. Given what I'm doing at the time, I guess it's Intellisense related.
Even Visual Studio has noticed it and complains with messages like the following:
"We've noticed that extension 'PHP Tools for Visual Studio 2019' is slowing typing performance."
"Visual Studio stopped responding for 5 seconds. Disabling the extension PHP Tools for Visual Studio 2019 1.51.13247 might help."
This is happening every five minutes or so.
I don't know what sort of projects you typically test on, but this isn't a massive project by any means. Around 115000 lines of PHP split over 620ish files.