And yet, somehow, no one has done anything to address the inherent issues for colorblind developers. All of these colorization add-ons are woefully inadequate in that regard.
Seems like a fundamentally unsolvable problem. These techinques use a spectrum of colours for deeply nested brackets. (If you only have one or two levels of brackets then you don't need the colourisation in the first place.) But colourblind users fundamentally don't have that many choices of colours to pick from in the first place.
It's not unsolvable. Colorblind people are missing one axis of color (such as the red-green axis). It is perfectly mathematically possible to pick colors that do not only differentiate along this axis, hence this option in many AAA games.
Here's an online simulator to see what colorblind people of various types see. Note that if you yourself try this and the colors for one of the examples don't seem to change from the "normal" version, see your eye doc...
This might be my own personal experience, but one effect of my colorblindness is that I place far less emphasis on color-coding in the real world--I'll subconciously ignore things like status indicators. When I think of alternative solutions here, I tend to reach for variables like font weight instead.
A different spectrum per type of colorblindness. It should work fine, unless you're completely blind to all colors, which is a very small proportion of colorblindness, most are only lacking perception of one out of three colors.
You can already do that: in the settings.json under workbench.colorCusomizations, change editorBracketHighlight.foregroundX where X is the level of bracketing you want to modify.
In practice, though, the reduced color vision combined with the small target that is a bracket (color vision degrades for smaller objects), means that this is of limited usefulness.