I was able to install Mojave 10.14.4 b3 this morning and the game now appears to work without the red tint. There is still a bit of a flicker, kind of like a lightning flash every now and then, but the game is at least playable with the correct colours.

I made a small standalone campaign mod for DOS2, 'Treasure Hunters! https://steamcommunity.com/sharedfiles/filedetails/?id=1594027212
Mostly I make music: https://www.sjatr.com

Fav RPG games: Bard's Tale, Baldur's Gate, Neverwinter Nights, D&D Gold Box, Diablo, Divinity Original Sin.