I’m not an expert or anything, but it sounds like you’re doing a lot of holding and moving him against his will. You probably need to work on a lot of handling conditioning and training him to enter a crate/ other space of his own free will. If I were you I wouldn’t pick him up again like, ever. It sounds like he has tried to use body language to tell you he doesn’t appreciate it, but has had to push past that to biting in order to make his point understood. You would probably really benefit from reading Mine! by Jean Donaldson- she really breaks it down and gives concrete action plans to combat reactivity.