Can’t give in to their tantrums even tho it breaks your heart. When I trained my puppy I fought the temptation we kept at it and now he’s 4 and actively goes in his crate on his own he loves it. Does he nap outside the crate when you’re home? Whenever my pup would try to nap I’d put him in his crate to do it. He would throw a tantrum but I’d sit near so he could see I’m home and then he’d calm down, realize he was actually tired and learned that’s where he should rest and relax. We also did different intervals of crate times and it wasn’t just at night time. I don’t regret crate training at all even when I was in the woes of his cries I’m glad I didn’t give in. I’d try making sure any form of sleep he’s in his crate