Female novelists seem to be getting a bit of a bashing these days. Some literature courses offer trigger warnings for anyone frightened by the “toxicity” of Jane Eyre or Northanger Abbey. Tom Rachman’s The Imposters doesn’t let them off too lightly either. His first novel, The Imperfectionists, focused on journalists. Here he offers a convoluted study of a different sort of writer, the ageing novelist Dora, in a treatment that is not unfeeling, though needlessly contorted.

The book, one gradually realises, is supposed to have been written by Dora – Rachman is playing the ventriloquist here, with Dora his dummy. What we get are disparate pieces of fiction that Dora is presumably working on (mostly in the present tense, alas – almost always a mistake). These stories within stories, combined with scored-out sentences, snatches of her diary and Dora’s own cameo appearances, coalesce into a “punishing self-portrait”.

Dora claims to be retired, but can’t stop writing. She’s like a cement mixer, continually churning away, propelling aspects of her past into new formations on the page. She also toys with the idea that “a manuscript could be about writing itself”. Please, no. But that is what this novel becomes, through various stabs at narrative. Individually, they are absorbing – but there’s a mystifying fluidity and self-regard to it all, with one unrelated thread leaching into another for no discernible reason. You can lead your readers to truncated plots, but can you make them care?

Writing about writing about writing is a tricky exercise, and a pretty thankless one. It is perhaps particularly brave to write a novel about a weary novelist, and this is not made more palatable by the flat tone, belittling characterisations (“sideburned Glaswegian”, “middle-aged Persian woman”, “plump pharmaceuticals rep”), and sloppiness (people fall “under a boulder of illness”; bookcases “run down the wall”). The only question is, should this stylistic carelessness be attributed to Rachman, or to his scribbling protagonist?

For a pensioner confined to her London house during Covid, Dora is surprisingly cosmopolitan. She sets her fiction in Paris, London, LA, India, Australia and the Middle East, and her characters include backpackers, nihilists, delivery cyclists, climate-change activists, rightwing extremists, political prisoners, thugs and psychopaths. And … more writers! There are so many writers in here, in fact, that it feels like there’s a David Lodge satire trying to burst forth.

Dora has had lovers, children and some literary notice, but, at 73, she’s lonely and believes her work is no good and her career over. The pandemic hasn’t helped. She tries to lure strangers in for coffee despite social distancing rules, then quickly finds them dull. They find her weird and aloof. Dora’s not-unreasonable worldview is: people fail each other, they can’t love, they’re all poor artists, fakes and has-beens, and they live too goddam long. What’s more, the Earth is dying.

There are livelier moments. In Soho, Dora encounters a load of “hipsters, darting hither and thither, like a dance number involving portable coffees”. In an episode abruptly set in 1974, Mr Bhatt, a low-grade Indian public servant, decides that overpopulation can only be combated by rewarding the childless, taxing babies, encouraging suicide and enlisting the press to out the most prolifically multiplying couples as the “Worst Family of the Week”.

In a more contemporary section, Barry, a hack novelist floundering over what to write, commercial fiction or heartfelt, jets off to a book festival in Australia to commit faux pas after faux pas. At his minimally attended event he manages to make offensive remarks about sexual molestation, disabled people and even Malala. Having binned a free tote bag full of books by his fellow writers, he then meets them in the hotel foyer and together they all watch as a cleaner drags a transparent rubbish bag full of their books out of his room. There are a lot of books thrown out in this novel: books trashed, dumped, shunned and despoiled. In The Imposters, books and writers are all on their way out.

By “imposters”, does Rachman mean hypocrites? He has skewered them in previous books, and there are certainly a lot of phonies here: writers who claim their fictional characters are more alive than real people; chancers who translate clickbait conspiracy theories for a modest living, apathetically inciting world unrest; leftwingers who quail when forced to mingle with genuine torture victims; and would-be environmentalists happy to fly halfway around the world, so long as they can eat sustainably once they get there.

Rachman is observant about Dora, and novelists as a tribe: their urge to steal stuff from other people’s lives, recycle their autobiographies, and pretend obliviousness to their habitual neglect and betrayal of others. But after clambering through Dora’s fragmented story you begin to think The Mikado’s merciless Lord High Executioner might have a point: “And that singular anomaly, the lady novelist – I don’t think she’d be missed, I’m sure she’d not be missed.” That doesn’t just apply to female novelists.

• The Imposters by Tom Rachman is published by Riverrun (£16.99). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply