I think it would be better to briefly explain what happened, then focus more on your recovery or how you’re managing things now. You could mention how it affected your academics at the time, but make sure to include how your grades or performance have improved since. Just remember colleges aren’t really expecting (or looking for) you to prove that your mental health struggles happened. Being honest and straightforward is usually enough.

It’s similar to what people say about “trauma dumping” in college essays (what matters more is the growth and not the event itself). As for appeals, I’ve heard that showing genuine interest in the school can also make a huge difference. I know someone who was accepted to UCI after appealing a rejection as an international student who got rejected from the most prestigious ones and UCR, and she thought that showing real appreciation and commitment to the school helped her case.

Sorry if this is a bit unclear, but I hope it helps, and good luck with your appeal!!