I totally agree with boing!
For one, 12pm, I’m assuming you mean midnight? For buns, that’s “PARTY PARTY PARTY” time. At that point, your bun probably wants to run around. Ive recently switched to night shift stocking so my buns are super eager on the weekends when I’m up all night lol.
Buns are also super routine, so, if you put her to bed at midnight one night, then 8pm the next, she will likely be upset. My younger bun will actually go in his cage around 11pm on his own (kinda scary… xD) just because that’s the time Ive always put him up since his first day home,
My older one is a little more difficult about bed time, but food! Her food bowl is in the center of her cage so she has to jump in to get it. My bun absolutely looooves her pellets, so, I only feed her the pellets before bedtime. She has gotten to the point of “OH, FOOD BAG. FOOD BAG MEANS FOOD” (Kinda like the binkybunny ad “did something crinkle? I know I heard a treat bag crinkle! once you crinkle, its all over…. I’m onto you!” Rabbits really are like that when they find something they love lol) so, Ill make sure she hears it (I actually use a metal bowl to transfer the food from the bag to the bunnys’ bowls as it makes more noise) to which she generally comes near but doesn’t go in her cage. At that point Ill step away, and within a minute or two, boom, shes in her cage! and shes occupied so no evilly innocent sad eyes for a short period!
For the sad eyes, the biting of the cage, all that stuff, both my buns do it now and then but nothing like they used too. I just kinda turned it into a cute thing “awww is someone having a case of the grumps” “awww someone is playing music with their teeth again!” and, I dunno why, but, I think it made them realize “dang! shes not giving in!” I guess you could compare it to a child. Some children are put in time out chairs, corners, etc. The first time it happens, they are going to scream, whine, fit, smack stuff, etc, but, when they realize they are getting nowhere, or getting worse punishments, they quickly start giving up on it.