It's better for the humidity to rise at night rather than fall, I would spray the tank before lights off

I'm surprised that the frog is turning down superworms, it's basically junk food to them and something that they'd enjoy. Expect to see poops at least once a week and preferably more often

Have you been handeling the frog just now or fiddling about? This can prolong the adjustment period. Whites can eventually be handled frequently once they've settled down