When I was first getting into programming and computer science as a student, I was so into these kinds of super-customizable rabbit holes. My whole life pretty much centered around the keyboard and terminal. I was all in on knowing everything about the entire stack and making it do whatever it was I wanted. I'd spend hours to save a few keystrokes. That wasn't so much about the productivity trade-off as it was about…
In no way do I want to come off as rude with this comment, but to me what you are saying is not at all different from "when I was young I used to work out and eat healthy... a couple of decades later, I just fund it all so exhausting". Customizing your computer environment is good. Eating healthy is good. None of those need to end up in a "rabbit hole". Everyone can be tired of life and give up due to exhaustion, but…
The thinking environment of choice of the most productive, smartest person I've ever worked with was .. a notepad. Not Notepad, a physical A4 ruled paper notepad and an ordinary gel pen. The actual development inevitably required some typing, but the thinking process and its associated diagrams, calculations, and scribbles for the kind of maths-heavy work he was excellent at worked best on paper.
(I currently have vscode open .. and actual Visual Studio, and IntelliJ, and notepad++, each with a different set of files open in different languages.)