Not sure how I would use that. Do you mean 2 custom colors to change both the default orange and blue? I can perfectly distinguish them when they're on a bolder shape (๐ ๐ต), it's just a lot harder (or sometimes impossible) on a thin line/symbol.
Again, the most efficient way to handle it would be to have a different style for the selected arrow (bolder, bigger, underlined or circled for example), on top of its color. It would then work as well in bedtime mode (b/w and low brightness) for everyone, not just for color blind people :)
I think bedtime mode activates by default on newer Android devices after 10pm when the phone is charging. That's how mine (OnePlus) was set up.
I see my initial reply was upvoted about 30 times. Statistically speaking, I don't think these would be only from color blind people
There's this workaround that works well : https://www.tomshardware.com/how-to/install-windows-11-without-microsoft-account
It's definitely not for lambda users and a real pity that we have to resort to this, but it does the job (for now).