Looking at the screenshots posted a few messages back, which are VERY
busy, I would really appreciate an option to disable a few fontification
rules or, conversely, disable all but a few of them. Ideally, this
should be done through a generic mechanism that works across major
modes.
I believe that history suggests that a better approach is "fontify everything and provide a setting that gives most of them the same appearance", assuming that the combination of tree-sitter and fontification is performant enough. This also enables some interesting features that were tried way back in the days of hilit19 like "transiently highlight everything of *this* type, but not all types". Somewhat like how isearch (occur, et al) can highlight literal duplicates, but based on shared semantic properties instead.
I couldn't tell you offhand if the current tree-sitter performance for fontification is strong enough for this sort of thing or not, and I suspect the noverlay branch also has some impact here.
Hope that helps,
~Chad