Saw it yesterday and liked it much more than I'd expected to. Chalamet is amazing; he somehow manages to imitate not only Dylan's singing voice and guitar/harmonica playing (he had to learn all of that; he'd contracted to do the movie before the pandemic, so he had years to perfect it); he even manages Dylan's posture, gait, and speaking cadences, and his "cool" vibe, which can read as arrogance (or just self-aware certainty of his own genius).
Supporting characters are also great impersonations (of Joan Baez, Pete Seeger, and especially Johnny Cash).
Read Richard Brody's review in the NYTimes. He complains that the film doesn't really rise above impersonation, which has some validity. Still, how can a mere movie give much insight into the mysterious cultural force that was (is still) Dylan?
"Don't Look Back" is a must for anyone who wants real insight into Dylan, since it's a masterful documentary that spans roughly the same years as "A Complete Unknown." Chalamet clearly learned from it. And, FWIW, Brody likes "I'm Not Here," which is more "ambitious" as far as attempting insight into Dylan's character in clever ways (I mean, Kate Blanchett plays Dylan in one of his periods!).