you can request to add categories. either contact the mods, or fill out the form in this guide
https://www.speedrun.com/post/p1v74#:~:text=Go%20to%20the%20game%20page,and%20click%20%22New%20Category%22.&text=%40Laika,the%20series%20moderators%2C%20ask%20them.&text=Select%20Single%20Game%20and%20set,as%20'Miitopia%20Category%20Extensions'. this is the official post on how to do so. GL!!
@Apianbelle That form is for a moderator to request a new page for category extensions. SM64 already has a category extensions page.
If you wish to replace your twitch highlights with reuploads, please edit your already verified run rather than deleting the verified run and making a new submission. This makes it a lot easier for us to track which submissions are reuploads and should be less work on your part as well.
If you need
