Career progression and critical acclaim (2017–2021)
Salmaan had three film releases in 2017. He first appeared in the Malayalam film Jomonte Suvisheshangal opposite Anupama Parameswaran and Aishwarya Rajesh. Despite comparisons with the 2016 Malayalam drama Jacobinte Swargarajyam, the film did well commercially.
His next appearance was in another Malayalam film Comrade in America. The Hindu called it "Dulquer's big hit of 2017". After a cameo appearance in Parava, He then portrayed four roles in the Malayalam-Tamil bilingual anthology Solo. The film faced immense backlash from the audience. Despite negative reviews, his performance was well received and Deepa Soman noted, "Dulquer, who plays four distinct characters, has also showcased a worthy performance. Especially as Siva, the gangster, he looks a lot more convincing in Solo than in other movies in which he has tried the role."
In 2018, Salmaan expanded beyond Malayalam films. He first made his Telugu film debut with Mahanati, playing Gemini Ganesan opposite Keerthy Suresh, who played Savitri. His performance earned him the Filmfare Critics Award for Best Actor – Telugu, in addition to his first nomination for the Filmfare Award for Best Actor – Telugu. The film emerged as one of the highest grossing Telugu film of all time. Hemnath Kumar noted, "Dulquer is terrific as Ganesan, and it is his charm and flamboyance that pours life into the narrative throughout the first half." Following this, he made his debut in Hindi films with Karwaan, co-starring Irrfan Khan, Mithila Palkar and Kriti Kharbanda. The film was a moderate success at the box office. Anna MM Vetticad noted, "Dulquer gives a gripping performance as the self-effacing Avinash. He and Irrfan are absolute dears in a sweetly understated road flick."
Both of Salmaan's 2019 films performed poorly at the box office. He first appeared in the Malayalam film Oru Yamandan Premakadha opposite Nikhila Vimal. He then played Indian cricket team's captain in the Hindi film The Zoya Factor opposite Sonam Kapoor. Despite mixed reviews, his performance was positively receive, and Nandini Ramnath was appreciative of his "camera-friendly manner and outsized charm" that stands out.
Salmaan appeared in three films in 2020 and also launched his production company, Wayfarer Films. He first appeared opposite Kalyani Priyadarshan in the Malayalam film Varane Avashyamund, which was his first production. The film emerged as one of the year's highest grossing release. Cris of The News Minute stated, "Dulquer perhaps gets the least of the screen time and the actor appreciably does his little part well and lets the seniors take over." He then played a con man opposite Ritu Varma in the Tamil film Kannum Kannum Kollaiyadithaal, which earned him his first nomination for Filmfare Award for Best Actor – Tamil. S. Subhakeerthana noted, "If we look beyond Dulquer's box office pull, it is his energy, screen presence and earnest approach to acting that takes the cake in the film." The film was a box office success. He then appeared in a cameo in his production Malayalam film Maniyarayile Ashokan.
His only release in 2021 was the Malayalam film Kurup, where he played the titular role of Sukumara Kurup opposite Sobhita Dhulipala. The film marked his third production venture. One of the highest grossing Malayalam film of all time, it became his highest grosser at that time. Haricharan Pudipeddi noted: "As the central character, Dulquer plays Kurup with unmatchable swag and effortlessness, adding swag and sincerity while playing the elusive fugitive."
