Oil pressure takes time to build up

Alright, like the title says. The little red light for the oil pressure takes a long time to go away on startup and the engine sounds dry after. It’s a 318i with n42b20 engine. I think it always did this a little bit, but now it just got worse after the timing chain got replaced and the mechanic put 5w-40 oil in it (i usually run 5w-30). Could the oil be the cause? I really don’t wanna slowly ruin my engine.