David Goodhart of Anywheres, Somewheres fame, is one of those who characterise current populisms as demand for a social democratic 'left' turn on economics, alongside a conservative 'right' turn on culture. This sounds plausible given the state of public opinion in Europe and America, but despite the immigration issue it can be revealed as glaringly unrealistic.
First, since the 18th century culture in the West - and often elsewhere - has consistently gone its own way regardless of the political class. At present, it is possible (with difficulty) to control immigration (not culture) without creating a closed society, which Goodhart acknowledges no one wants. But who is going to warn the public about the links between climate change and migration, and in particular prepare for a fresh wave of migrants from flooding Pacific and Caribbean islands?
Second, the standard problems of public debt, aging populations, and need for extra spending on defence, will ensure governments cannot run political economy from the 'left' even if they want to. Rather, as Sir Kier Starmer is finding to his cost, it's a struggle to keep supporters on board and handle welfare at the same time. That in itself is likely to keep culture as the refuge for left sympathisers that it has been for at least a century.
Goodhart cites Denmark as a case of his proposed settlement being put in practice. I don't know about Denmark's economic situation - maybe that is more sustainable than most democratic states right now. For now it can 'control its borders' without isolation, climate change permitting.
The upshot of all this is that Goodhart would be better served out on the stump urging radical action on climate change (maybe not net zero) so that potential migrants can stay at home.