CL is really not the answer. In fact, most Lisps probably can't beat Elisp for the simple reason that majority of Lisp dialects are very data-oriented, while Elisp is specifically text-oriented and that's not the property of the language but the runtime - implicit current buffer, an implicit point, global match data, etc. You can't simply replace forty years of packages, where every single one of them assumes the exact Emacs runtime. Lem's problem (or any Emacs alternative) is that it has to be much better to justify migration, and nothing is much better than Emacs at being Emacs.

I've never gotten lem to display anything readable in a browser tab over 2 tries separated by 6 months. (I didn't try the terminal front end.)

I keep meaning to check out Lem. It just pains me having to get my setup set up all over again. But, long term Lem is probably the move.

It’s a better lisp, too. Elisp really sucks and is my least favourite part of emacs, which I use daily.