It's such a quirky and messy ecosystem. So organically grown over decades. Doing any complex layout is a struggle of trial and error and searching for advise, there's so many ways to do the same thing, you end up combining two dozens sometimes subtly incompatible packages, you end up gardening your own templates over time with meticulously embedded commentary to keep the complexity at bay, you struggle to understand what's going on under the hood to reason about what's happening, you dive into source files, etc.
But the thing is ... at the end of all that labor, it all works and the quality of the output is simply second to none. Making a beautiful doc with it makes you feel like a master carving a famous statue out of marble. Ultimately it feels like it couldn't have been done any other way, and you do love the end result dearly.
I do keep half an eye on https://sile-typesetter.org/ to see if it may become sort of a consolidated "LaTeX: The Good Parts" over time, replacing the cruft with a new baseline, but in the meantime I will keep treasuring my little zoo of .tex files.