That’s the nearest option I could find, and I agree, it isn’t a great match, but then I don’t think anything can be.
The thing is, Karabiner is doing some low-level wizardry, and it is the only thing that I’ve ever come across that goes down to that level to do this sort of thing. Everything else I’ve ever seen always piggy-backs the work being done and has Karabiner as a prerequisite.
Personally, I’ve never used Karabiner. I rely on my more traditional key combinations, Alfred workflows, Keyboard Maestro palettes, a Stream Deck and/or Touch Bar (Better Touch Tool FTW!). I’ve got so many ways to trigger so many things (often multiple ways), that the cognitive load of adding a hyper-key with Karabiner and just the fundamental need over the hundred of options have just never taken me down that path.
As it happens, I also *really* don’t like the idea of something poking around at that level without it being part of the OS or being developed in part with Apple. I remember some of the really low-level stuff I used to use at work on Windows that IBM developed in partnership with Microsoft, and even that caused headaches in the real world a lot of the time. I don’t want those headaches any more, and this sort of app can definitely affect system-stability, which is presumably what the OP has experienced.
The issue log on GitHub also makes for very interesting reading. While it is very powerful, the developers are absolutely doing some great work, and it is an app beloved of many of the Internet’s more prominent Mac users, including yourself, some of the issues that seem to make it through put it in the ‘too risky’ bucket for me.
I might be mistaken, but I thought that I recalled that Hammerspoon had to be configured for Hyper Key in each application. However, I am not sure that is accurate or just something that I (mis)read awhile ago. I was about to try to set it up when Karabiner was released for Big Sur.
Okay so I was able to bind Caps Lock to F18 and created the launch agent so that this stays after reboot. I am kind of lost on how to bind F18 to the four other keys (cmd+opt+control+shift) via Hammerspoon tho.
Huh. I don’t think I’m getting a KP on shutdown, but every time I restart my M1 MacBook Air, I get a message that “Your computer was restarted because of a problem” so I wonder if that problem is Karabiner.
Did you try logging out before you shutdown? I wonder if there’s a way to unload Karabiner on logout, if it’s not already done.
You are experiencing the same thing I am. When I try to shut down all looked fine except for a brief pink screen would flash and I got the error on startup. Here’s the bug I’m tracking on GitHub. Lots of other users have reported the same behavior. I did not try logging out, but removing Karabiner resolved the problem for me entirely.