Series peaked with Conjuring 2
Although Conjuring 2 is still relatively mediocre as far as crowd-pleasing supernatural spooker flicks go, it was way more entertaining and engaging than the boring mess that TDMMDI became.
In this one, there are maybe two decent setpieces that are quite effective, but they're slotted into a film that largely feels bored with itself, and the actors look so disinterested as if they'd rather be somewhere else.
Big disappointment that shows this series' formula has exhausted itself.