Original Super Mario Bros. 2 has categories called Any% or all levels [character_name] only, so why can't it be created here too? As well as some (if not all) other categories from here https://www.speedrun.com/smb2ce I think they would fit this game.

This game is way less popular than original SMB2, that's why.

I know it, but still why not to add them?

Because we don't know if people will run it, which runs the risk of ending up with empty leaderboards. If you want it to be added then your best option is to do a run yourself first and then talk to the moderators.

Fair enough. Gonna work on it as soon as it will be possible.

I’d love to have Any% or All Levels Character categories as well. Can I just try them and send it to a moderator? How would I submit such a run? One possibility is to share a YouTube link to it?

These categories have now been added under the Misc. tab for now https://www.speedrun.com/sma#Single-Character