That’s as far as you can push a ski jump type aircraft carrier.
Not just a STOBAR thing.
CV-17 went to sea with a partial airwing (I estimate 60%ish load).
Given that, and given that they probably aren't doing intensive flight cycles (why would they -- that sort of thing is better practiced closer to home where there is plentiful easy land divert bases if needed), then 80 fixed wing sorties over three days is about reasonable.
I.e. what we are seeing almost certainly isn't their peak actual sortie generation capacity.
Also keep in mind J-15 is a pretty big aircraft. If J-XY/35 is compatible with STOBAR carriers, then I imagine CV-16/17 will see a slight boost to their sortie generation rate given their smaller footprint.