I have a couple ideas for a Sonic Mania Category Extensions page...but cannot make it unless I am a mod. Would someone be willing to add me as mod or make the CE page and add me as a mod to that?

There are strict rules for becoming a moderator here. You have to vanquish the other mods in a trial by combat. Best of seven series - Sonic, Tails, Knuckles, Mighty, Ray, Sonic & Tails, and Encore Mode: it's you vs. seven mods and you must complete the runs in one sitting. If you finish before they do, you are worthy of mod status. If you can't beat them, you forfeit the patents to your ideas for category extensions and the rest of the moderators profit off them, plus you do all the rest of your streams for the year in a Tails onesie. Are you prepared for this?

To be honest, there are already 14 full-game categories (NG and NG+ for all characters, S+T and Encore Mode), along with all ILs (5 characters, Mania and Encore mode). I don't see why create leaderboards for even more categories before checking if there are enough people to run them.

Wanna become mod here how do i do that?

You have to run the gauntlet. Y'all already know what it is.

Okay and how do i run the gauntlet?

Scroll up, young Champion. Your journey begins north of this post.