It is an endless game, that is the reason it's not allowed apparently. Let me give you a bunch of categories people could run.

Die% - How fast can you die.

10-100-1000 kills %, speedrunning getting kills, sounds like something that would qualify.

Louisville % - From Muldrah get to Louisville. Sounds like something else that could qualify.

Extraction - Using the Wolf's Extraction Quest mod, get to the choppa.

Max x Skill % - Can take all of the skills, and make a speedrun out of those. Maxing out a skill.

There are plenty of ways to speedrun this game, imo it's kinda ludicrous that it's not allowed on here. I could probably think of more, but honestly with a little imagination I'm sure people could come up with more categories.

dont give the reasons to us. give them to the mods who add games. there is a box specifically for this in the game submission form.

but these all sound like category extensions (extremely arbitrary goals often jokes) and not real full game categories (like you know any% or 100%) which id say is why they are not enough. though they dont sound like full game categories because they arent them as there is no "full game" in something that never ends