I’ve been running this on one of my desktops in an effort to wean myself from spacemacs and doom.

I generally like it but the one thing I’m really missing is the spacebar concept from spacemacs / doom. Anyone know a way to shoehorn that in? Or any tips for how to do without it?

As another commenter pointed out, what you're probably looking for is general.el: https://github.com/noctuid/general.el