It seems everyone else here has it mapped to Ctrl, and here we are with it mapped to Esc... is there something I don't know? Esc works wonderfully with Vim, even better than Ctrl-[, but perhaps there's some other reason?

mapped it to ESC because im using a mech keyboard who's ctrl is reachable by my pinky. I tried remapping it to ctrl, and mapped 'jk' for esc in vim but it didn't work that well for me