Would it be possible to have a subcategory of a subcategory?
My plan is to have a subcategory for each release of a game (since some things were changed) and then a second subcategory for emu/not.

Alternatively if one platform would always just appear on top even if it had slower times (similar to min captures/items in other games) that would work too.

You can mix different sub-categories to get this effect I guess. Look at this example: https://www.speedrun.com/mcce#All_Versions

I don't personally mod games myself, so I don't know how to exactly achieve this effect, but I thought I should just point out that it exists.

While it‘s possible to have have multiple subcategories (like Monsh showed), you cannot have subcategories of subcategories. For example, it’s not currently possible to have a second set of subcategories that change based on what subcategory is selected or only have a set of subcategories appear when another is selected. I wish these things were possible within the site but as of now, it isn’t.

@Garsh the thing he showcased seems good enough to me to achieve my needs even if it doesn't look the prettiest. Thanks for the help @MrMonsh

Although something where it is shown, but always shown below other runs would be preferable if that's possible (in a similar way to how low% is handled).