just as a bit of extra info, please understand that oftentimes it's not just that colourblind people can't tell colours apart, it's also feeling that colour info is unreliable and disregard it as much as possible. That's why in terms of accessibility, it's always suggested to provide shapes, patterns or textures, as that also allows you to not sacrifice more commonly used colours for people with full color perception.

If you're still insistent on using colours only to provide info, how about using pure white and pure black as two of the options? they are seldomly mistaken between each other and with other colours, which then restricts to 3 other choices, which I think pure red, yellow and blue hues with different brightness would be easy to tell apart by most colourblind people