Factorio uses a lot of colors, especially on the map, and the mod itself helps but its not enough for some subtle things like the range of an artillery unit on Gleba (yes the issue is that specific to my protan eyes, I can see it just fine on every other planet). Windows has a nice color filter feature where it swaps all the colors from one set to a slightly different set based on your own type of colorblindness, which by itself is not enough to be able to see all colors, but it will often switch which ones are differentiable. Even more helpful is switching back and forth repeatedly, making different color borders much much more noticeable which is what I want to suggest for this mod.

I would like the ability to pick 2+ colors for things on the map and have them flash between the two (like red, and a slightly brighter red for the change in contrast) to help distinguish colors better. Idk if this is possible or feasible.

Unfortunately, this is not possible. Factorio only allows for modifying colors used for the map while the game is first loading. This is done through the UtilityConstants API.

I like the idea of a highlighted border. That would improve contrast a ton. Unfortunately that is not something that can be done as a mod, so you would have to create a suggestion on the forums.

I recommend setting your artillery range color to something with a high alpha value, and then to get the flashing you want, click repeatedly on the enable/disable turret range button in the map view.