Genuinely, yea, it is hard to come up with a proper character design. Even I can't nail mine first try heh
But let me give you a word of advice,
Make it exist first. Whatever you have in your mind, you can sketch it out and work along. You can also go messy with it, don't overthink it you know? Go with the flow!
Also respect yourself. If the design isn't as good first try, then don't worry, next time you can retry, as more times as needed, but don't let the frustration overtake you or prevent you from doing other things either, or it'll develop into burnout.
That's my advice as of now, hope I said it well because it's 2am here
Good luck!