8 month old lab mix has decided this week that his crate is a torture chamber and i dont know what changed

Looking for advice from anyone who has been through a sudden crate regression. Our lab mix Otis was crate trained from 9 weeks old. He has slept in his crate every single night for 6 months without a peep, naps in there voluntarily during the day, walks in for treats, all of it. About 9 days ago this all stopped working and i am completely lost.

It started one night when there was a thunderstorm. He whined that night, which made sense, we let him out, he calmed down, slept on the floor next to our bed. The next night, no storm, no obvious trigger, and he started panic barking at 11pm and wouldnt stop. We gave it about 25 minutes thinking he would settle and he started actually scraping at the crate door with his teeth. We let him out before he hurt himself.

Since then we have tried covering the crate with a sheet, leaving a worn shirt in there, frozen kong at bedtime, white noise machine, moving the crate to a different room, moving it back, ignoring the barking (4am barking with thin apartment walls is not really an option), and 2 nights ago a mild calming chew the vet recommended. Nothing has worked. He will sometimes go in voluntarily during the day for a nap, but at bedtime he plants his feet at the door of the crate and you can see real fear in him. Like the kind where his whole body goes still and he wont take a treat from my hand.

Is this just a fear phase we ride out? Should i be worried theres something medical going on i am missing? Has anyone had a dog do this and recover, and how long did it take? I am so sleep deprived i cried into a bowl of cereal yesterday so any input is welcome.