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.

just the ability to change the bracket colors with reasonable default selections for colorblindness seems like a more than reasonable request

The extension already had a setting to tune the color palette even before it was merged into VSCode core.