Hello,
Further to your message about colour combinations, canva[dot]com has a colour picking tool that allows for four contrasting colours at a time and they're really very different.
It's going to be hard to describe what I mean without you seeing the tool itself, but you can start with one main colour, select a position on the colour wheel, and the tool will generate three other colours that contrast.
My thought here is that it's possible then to move the main colour around the wheel and get another 4 contrasting colours, or to move your main colour further toward light or dark and get more colours that way. Hex codes are given for each colour shown.
If you were then to place these colours on a dark background and separated from each other, you'd then be able to see which colours are more easy to distinguish from one another. High contrast is essential in a game that relies on differentation.
Don't be afraid to go with fun colours as well as "dull" ones - more of the former, a few of the latter.
Try starting with #A61EE1 and see the other three colours that occur at 90° around the colour wheel. And, of course, you can choose a colour palette that you prefer - this is just one I thought was nice, the blue and green are particularly pleasing :)
Other commenters have mentioned that there's no accessibility option for colour-blind players, which is always going to be a thing.
My suggestion would be to see what the others who've developed this game have done before you, it's often some sort of texture pack applied over/instead of the original colour. You may do well to find someone with total colourblindness to work with to get their thoughts on the matter. My own father lived in a completely greyscale world, it's not as uncommon as you'd think.