Why not allow same colour players in the same game? With 100+ players, it is not possible to border everyone, so you can manually set different colours for neighbours.
In fact, why even have different colors? Let's make everything the same color as nutral /s
Anyway, the current amount of colors is the explanation behind 40, instead of say 30 or whatever number. A somewhat common suggestion is to add patterns to the colors, making it possible to both increase the number of options a lot and making it colorblind friendly. But yeas, clearly WZ should advertise it'self as the latest Battle Royale game :P Having games with 1000! players in them :D