from @daedalus's Crux newsletter:

"Throughout this weird thing I guess I'd call a career, I got used to this way of working. Each engagement tends to follow a similar flow: the initial enthusiasm that comes with the novelty of a new challenge, the unsettling period where you know quite a lot about a place but keep tripping over new rakes and uncovering new landmines left there by your predecessors, the comfortable period of an established rhythm that risks settling into complacency, the growing sense of unease either from unwelcome, externally-imposed change or boredom."

that's exactly the same experience I've had in every job too