In my experience, the Gaomon s620 is perfectly fine for osu! and I'm only upgrading it rn because it's starting to have slight delay issues since I've had it for a long time. Especially considering the fact that you've only had your tablet for 3 months, I don't think upgrading would give you that much of an upgrade and if I were you I would save your money unless money is completely not an issue for you. That being said, the CTL-472 is technically better since it is from the reliable Wacom brand plus it has no built-in hardware smoothing, but in my experience the Gaomon does the job well and I have never noticed its smoothing until very recently when I've noticed that it has been increasing in delay, but that's probably just because I've had it for a long time under heavy use.