Well, going stir crazy is preventable. We could just relax a bit. Whatever happens, happens. It's out of our hands right now. You can still support a character without triggering your anxiety or everybody else's. K. Rool is a fun character. And his inclusion would be a good, fun thing. We shouldn't make our faves a toll on our mental health.
We can still support King K. Rool or whatever your fave is (since I know there are lurkers here) without making yourself feel upset.
And how about we don't close doors for K. Rool, whatever happens? That's the worst thing you could do IMO. Like if K. Rool is an AT, who says he can't be DLC? If that happens, we should do our best to get Sakurai to open that door instead of accepting it is closed. And sure there's reasons why they may not go that route but there's also reasons to believe they could. And that's enough if you want your character playable. To push, persistently and patiently, to keep the fanbase alive and make being playable possible.
Besides, I'm sure if other characters stay or are made ATs , like Ashley, Bomberman, Waluigi, Krystal, Isabelle, etc. we'll have many fans for many different characters working together to pull that door open together. Might not work but it's still worth a try.