Lem supports vim key bindings, according to its README.
btw, I don't have any issues with emacs keybindings, but I chuckled at the "Emacs RSI bindings" :)
In fact, I think vim keybindings are superior for editing - you can't beat hitting "." to repeat an action - but after using emacs for ~5 years I find myself in it a lot more than I expected when I started using it. The whole thing with key bindings is that for whichever one(s) you use your muscle memory catches up.