I'm very interested in moving from my Mac to a Linux system. The main barrier is my dependence on Jason Rudolph's Keyboard. Specifically, I need an equivalent to (S)uper (D)uper Mode. Super Duper activates vim-like keybindings when the keys "s" and "d" are pressed simultaneously. So j becomes ⬇️ and k becomes ⬆️. Is there anything like this built for linux?
After doing some research, I found XCAPE and caps2esc for remapping caps-lock. I also found this post about a hammerspoon equivalent. I have yet to find anything that implements Super Duper like functionality.