Then we’re not quite there yet. My Enemy of the State bracket had 27 people finish with maximum possible points. If that trend persists, top ten will be determined by who can sprint to the point max in the last sub. With this being a seven day event, no doubt some people (likely me included) will drop out of contention before that, but if there are even fifteen people who make it that far, their placement rewards (the only ones anyone cares about) will be dependent on waiting for the sub to open, then playing nonstop for the 2-3 hours it takes to finish the sub. I don’t think this is what anyone wants.
So my first suggestion would be to just allow people to tie for first place, but I’m betting that would mean giving out more 4* covers than you want (and probably worse, an unpredictable amount). But as a player, if knew playing perfectly got me first place, that would be pretty great.
My second suggestion would be to give bonus points for each mission based on how quickly you beat it. (even just a very small number like 1-to-10 because all we care about is breaking ties). This would mean that first place wouldn’t be determined by when you play, but how you play. Maybe you don’t want to make this a game where time to win is super important, so some other tie-breaking bonus point metrics could be: overkill damage, fewest number of turns, left over AP. I’m sure others could offer alternatives.
Or! You could build a survival wave mission into each sub that you can only do once and only do after the whole sub us cleared! It would have to be built to just ramp in difficulty so you play until you are defeated, and that gives you tie breaking points. I liked this best because it sounds like a fun challenge!