The Nun movies are actually prequels to The Conjuring series. While The Nun and its sequel take part in the 1950s, The Conjuring is set in the 1970s. Valak torments a young nun throughout the series, and it's only when Lorraine encounters Valak two decades after that we see the demon defeated.
Farmiga and Wilson briefly appeared as Ed and Lorraine in the 2024 spin-off film The Nun, focusing on the character of Valak in its "Demon Nun" form, who was the villain from The Conjuring 2.