In the past, MacOS has automatically made a folder of incompatible software that it leaves on the desktop. Little Snitch seems like something that could have been tested.

As far as I know Little Snitch uses a user-space Network Extension, which uses a public API added by Apple to the OS specifically to help devs move out of kernel space.

It is a commonly used extension, which was restricted so that I could no longe remove it. What's more odd is that supposedly I was running the latest version.