In emacs, c-x 8 RET prompts you for unicode character names (or hex) so for rare use you can just spell it out. There's also C-x 8 _ m for em dash and C-x 8 _ n for en dash. (Hit c-x 8 c-h to get a full list of those bindings, like any normal secondary map - they're about as idiosyncratic as the XCompose bindings, but you might find some of them "stick" in your head better (I personally like "C-x 8 1 / 2" better than "Compose 1 2" even if it's a lot more typing...)
>In emacs, c-x 8 RET prompts you for unicode character names (or hex)[...]
Which is super useful for hard space - non line-breaking space - so that one letter words don't appear at the end of lines.
Ooh, thanks! I blindly type c-x 8 RET, then finding myself stumbling through 9 different entries for Phi, but I hadn't explored the prefixes. I just realized I could create a custom which-key entry-point with my favorites in a prefix.
Also just learned about compose key apparently, and I noticed that I can program this split keyboard I'm using to turn that into a chord, anywhere!
Then an LLM told me that I can 3D print my own custom keyboard with 32 programmable layers. Everything is an infinite rabbit hole these days, how wild.