If Philip Roth had ever switched his attention from the great American novel and decided to write a lightweight indie dramedy, it might have turned out like this. Gabriel Byrne stars as poetry professor Samuel O’Shea, who is a cross between one of Roth’s protagonists and Keith Richards: a hard-drinking self-absorbed womaniser with a penchant for paisley scarves and chunky silver rings. It’s an insubstantial little film with slimly conceived characters, but Byrne adds at least 10 points to its IQ score and makes it twice as watchable.

Death of a Ladies’ Man begins promisingly enough when Sam walks into his Montreal apartment to find wife number two (she is half his age) in bed with another (even younger) man. Is it finally dawning on Sam that his charms no longer have the desired effect? That his narcissistic white masculinity is looking a bit 20th century? The evidence is everywhere: in a bar, his eye repeatedly wanders admiringly to a young woman reading a battered paperback. But instead of picking up the cue, she flicks Sam the finger. At the university, his gen-Z students look appalled by his drunken rock’n’roll lecture room style: throwing up in the bin and slurring scraps of poetry.

But just as you think this is going to get interesting, and Sam is on the verge of being cancelled, life does the job for him. He gets a brain tumour diagnosis – which at least explains his quirky hallucinations involving late night conversations with his dead dad (Brian Gleeson). Sam flies off to Ireland for a last redemptive visit, where there’s a silly shaggy dog storyline involving one last female object of pursuit.

There are a couple of great moments of comedy and poignancy, and the Leonard Cohen songs on the soundtrack do some heavy lifting. What’s missing is bite, any sense of Sam raging against the darkness. The result gives this film a bargain-bin literary movie feel, which is a shame because you sense Byrne could go the full Roth.

• Death of a Ladies’ Man is available on 25 July on digital platforms.