Some combination of Tampermonkey, MutationObserver and IntersectionObserver almost always gets there in the end, but despite having a default user script template with this exact skeleton it's a lot more of a pain in the arse to achieve what a simple CSS selector and some properties does in a few lines...
Exactly. And for me, that difference in PITA is the difference between fixing up websites in Stylus incrementally, spending a couple minutes for a CSS rule or three when something annoys me, vs. making a note on my TODO list to write the necessary code later, and never getting around to doing it.
