Ah, apologies for not seeing this sooner. AS of yet, we have not added categories for individual act levels. However, if the demand for it is high, we could attempt to add it into our leaderboards!
I think it would be a good addition to the Level Leaderboard section. Just levels with in-game timers though. (Time-based fight levels, ultra trials, tiny trials, and endless trials)
I know I for one would definitely use a feature like this to its fullest - ergo, I would grind ILs to fill up leaderboards just because it fits my playstyle of lacking consistency but solid peaks