It's my duty bring up that plain TeX, the Knuth language in which the large macro collection LaTeX is written, isn't as verbose and opaque as LaTeX when people complain about that.

It has the opposite problem where you may have more control than you'd like. But it is in some sense very simple. e.g. this is a valid plain TeX document:

$$\aleph_0$$

\bye

Things don't have to begin{ and end{ etc.

There are simple collections of useful macros like [extended plain] kind of like lodash where the aim is to enhance the classic syntax by ` input eplain` at the top, not take over.

NB: I was so proud to write my thesis entirely in [extended plain], but when it was time to submit it to the library they basically said, "That's nice, nerd, but we have specific style files." and I had to rewrite it into LaTeX anyway!

[extended plain]: https://tug.org/eplain/