2018, Mitchell founded the production company Amore & Vita Inc. and signed a contract with Warner Bros. Television. She was subsequently cast in the ABC television pilot The Heiresses, adapted from the book of the same name, which was in production until 2018, when it was announced that the show was cancelled. Mitchell also launched her travel brand, BÉIS in 2018. The same year, the horror film The Possession of Hannah Grace was released, where Mitchell was seen as Megan Reed, a "troubled ex-cop who takes the graveyard shift in a morgue". The project was filmed years prior, and she stated that it has been one of her more difficult roles to play. She stated in an interview with Collider: "I was playing a character who was dealing with major anxiety, and to be honest with you, before this role, I hadn't really encountered anxiety in my personal life. Getting this role and being in Boston and shooting it, right after coming off of PLL, to then leading this film, there was a lot of pressure. ... I had so many panic attacks, in those first three weeks of shooting, and it was only a four-week shoot. I feel like I was truly feeling what I think that character must have been going through." Upon release, it garnered a negative reception from critics, though Mitchell's performance was praised and the film was a commercial success. Since November 2019, Mitchell has portrayed Stella Cole in the Hulu comedy series Dollface, the best friend to Jules Wiley (Kat Dennings). The character initially drew comparisons to Mitchell's Peach Salinger on You, though she stated on the role that "Aesthetically, you can see a similarity but when you get to know Stella, she's really a wild spirit and a complete 180 from Peach. It was fun to go from that to this." Dollface is her first leading comedy role, and Mitchell, along with the acting ensemble, earned praise. She made her voice acting debut in the 2021 Netflix animated series Trese, where she provided the voice of the titular protagonist, Alexandra Trese. Personal life Mitchell supported Somaly Mam Foundation, a non-profit organization that fought sex trafficking, until it ended operations in 2014. She has also worked with The Trevor Project alongside the Pretty Little Liars cast and the NOH8 Campaign. She works with the WE Charity, which helps communities develop educational resources, and she