At first I thought her energy might've been down too, but as each song went by and I realized she was actually singing live it finally made sense.
We usually see her using a mix of prerecorded and live vocals or just lipping completely, so it makes sense she wouldn't go full owt this time to avoid sounding a breathy mess.
And I'm sure she was inside her head making sure everything went perfectly.
Hit this cue! Remember this move! Catch that mark! etc
Kween still got that fire tbh and her dancing is getting cleaner.