Sleep regression has entered the building!

My 19 week old baby is going through another regression. Between 2-5 he does not and will not settle. After an hour of trying to soothe him in his for and allowing a chance for him to self soothe, I pick him up and he’s asleep instantly. The second I put him down, nope awake again. He settled on his own in the cot but by the time I get into bed and comfy he’s awake and crying again. Any advice would be most welcome!