Newcomer-fans of Walton Goggins, sharing gifs of his stunned expression in The White Lotus, might want a look at this interesting but flawed movie: a heartfelt but frustratingly ponderous true-life story from the music world in which Goggins stars with Casey Affleck. Donnie and Joe Emerson were two brothers from Washington State who self-recorded an album in their teen years in 1978 called Dreamin’ Wild; it bombed, leaving crippling debts for their poor dad (played by Beau Bridges), who’d taken out bank loans to build them a log-cabin recording studio – but the record is then rediscovered 30 years later by vinyl hipster connoisseurs who can hardly believe the Emerson boys’ untutored rock genius.

The film insightfully shows how this deferred fame is not all good news; it has come too late for them really to enjoy it and Donnie (Affleck) has grown into a prickly, demanding creative personality who has been working desperately hard on his music career in the intervening years. He doesn’t know how to feel about being at last feted for a record he now thinks of as immature and outmoded and its belated celebration leaves no room for his wife and musical partner Nancy (Zooey Deschanel). Like many who finally get a break after decades of hard work, he reacts with strange indignation to the fact that he’s had to do without success for so long. As for his brother Joe (Goggins), who was only the humble drummer while Donnie did all the composing and playing and arranging, and now just works on the family farm, the resurgence of interest in Dreamin’ Wild simply re-awakens his inferiority complex.

Writer-director Bill Pohlad made the interesting Love & Mercy, about the Beach Boys’ Brian Wilson, and this has a similar before-and-after structure. The present day action is interspersed with scenes of the young Joe and Donnie, played by Jack Dylan Grazer and Noah Jupe. Yet however earnest and heartfelt, the film doesn’t tell us nearly enough, or really anything, about Joe. He has real heartbreak in his life and seems on the point of explaining this to a New York Times reporter – but is interrupted at the crucial moment. It is a powerful moment, but for some reason the followup never arrives, perhaps lost in the edit, and Goggins doesn’t have enough to get his teeth into. A shame.

• Dreamin’ Wild is on digital platforms from 14 April.