I recently bought a Ziyoulang K68 about 25 dollars. It is hotswap and it comes with red switches. I bought this keyboard for programming and gaming, but I don't have any idea about osu. Pls help
Unless it is a remarkably bad keyboard it will be fine. If it works for most games it will work for osu unless there is a very specific caveat. Red switches are generally held in high regard within the community, too (although in the era of rapid trigger they might not be viewed as favorably comparatively).