autokey
I accomplish the same thing with compose sequences, and by binding a keyboard shortcut in my desktop to call a script with wtype. It's not a cross-compositor solution though, as you'd have to manually setup binds in each of them.
I don't see much hope for this one-to-one unfortunately.
Scrubbing through the video, this hurts my soul
For variables bash has PE forms:
I miss these too much when I try Fish.