By the way, I do think TeXmacs is an Emacsen as it provides Guile/Scheme as an extension language, though I don't know how customizable it is. (I think the built-in REPLs for Python/Maxima/Scheme/... are written in Scheme.) And then, it does support quite some TeX commands (and you input them by pressing backslash followed by their command name), so I do think their "TeXmacs" name is very much justified.
You can find some example documents here https://texmacs.github.io/notes/docs/example-documents.html.
Other posts on the TeXmacs notes site discuss programmability with Scheme, typesetting math (https://texmacs.github.io/notes/docs/texmacs-math-typesettin..., shows how good the HTML export is), and more.
The best in-depth reference, even counting the astoundingly complete bundled manual, remains The Jolly Writer. It is a beautifully typeset book, available at https://www.scypress.com/book_download.html.
EDIT: missing link, typo
With stuff like Overleaf and plugins for modern IDEs, honestly I can’t say LaTeX is a bad experience. It does what it should.
To a lesser degree I also appreciated that the files have a similar feel to XML; I think it makes a lot of sense for this type of document.
I remember hearing about the macro system, but never looked into it. It sounded neat though.
When creating a technical document these days, I'd probably reach for typst though.
I do not have to collaborate with anyone in writing so it does not matter that there are no users among my colleagues.
In my opinion it is superior to all other systems I tried (I tried many and a lot, and all of the main ones). And, importantly, it is equal or superior to the other systems in _all_ respects.
"Integer multiplication in time n(log n)" https://annals.math.princeton.edu/2021/193-2/p04
I'd never heard of it but when I saw the title of this post I practically tripped over myself to click it. Latex and Emacs! From GNU!! How have I not heard of it?
A few lines in to the page. Oh it's nothing to do with either of latex or Emacs.
LaTeX: accomplished typography emacs: control of the interface
It delivers.