Since I am a mania player I find it easier to play taiko with downscroll rather than the standard right to left and I was wondering if it gives me an unfair advantage or is frowned upon

People do all sorts of things with their monitor settings for taiko, simply rotating your monitor is something anyone can do and is completely fair game.

this don't affect the skill cap much afaict, many players get really good even with horizontal scroll

peppy should add up, down, and right scroll for taiko in lazer ngl