> but I wanted to work out calculations on a single screen without the code/renderer split screen setup (having the math directly visible is a game-changer for doing long calculations, by the way).
If anyone wants to play with this there are 'online editors' so you don't even have to download/install software nowadays:
https://www.mathcha.io/editor is indeed much closer to TeXmacs than https://latex.codecogs.com/eqneditor/editor.php. No matter how instant the rendering is, the latter is still split-screen. It may not seem like much, but when you are knee-deep in a calculation the advantage of having a single point of focus for your eyes is huge (at least to me).
If anyone wants to play with this there are 'online editors' so you don't even have to download/install software nowadays:
* https://latex.codecogs.com/eqneditor/editor.php
This one renders on-screen, as well as allowing downloads as GIF/PNG/PDF/SVG to perhaps embed in other document systems. (Plenty of others as well.)