As of macOS 11, Hamachi no longer works in macOS. The above article lists changes in APIs that need to be made (probably not an exhaustive list). Apple seems to be now disallowing direct kernel modules. (This is probably why when I directly upgraded, it would only boot in Safe Boot and kernel panicked otherwise.)
@CaptainChunk The typical timeline is a few weeks after the OS is officially supported by Apple.
The old installer now works. Apple (rather than LMI) have fixed this problem. The issue where you couldn't click to approve the kernel extension was resolved in the release candidate.
Agree it still needs an update so it's no longer reliant on a kernel extension, but it is now usable.