this is of course far tougher. few CRTs are really bad, in that... most of the value is in the tube, and the tube is by definition pretty well made because if it isn't, it doesn't work. so that kinda leaves stuff with just very limited support circuitrry, and honestly... the original IBM MDA might be the best choice. It's so dead simple, it has almost no signal processing circuitry to the point that (according to legend) it can be injured by out of range input frequencies. but idk, i'll think about it more, maybe there's something worse.