NRFT but I don't know that Labour is losing their heartlands because of identity politics. I think they are just generally totally disconnected from what their ex-core voters want in life.
I know a very wide range of people, just by virtue of having been raised in one type of environment, travelled a lot, had a lot of jobs, so I talk to people from all walks of life, and the middle class lefty types (who make up a big chunk of Labour) generally have the wrong idea about the working class, which I see reflected in Labour comms:
Basically Labour see the working class as "vulnerable", in need of welfare and protection. They look at poor people and talk about safety nets and benefits, (which people DO need, and God knows the last 10 years has been carnage in their services that provide that support), BUT they never talk about aspirations, helping small business, getting ahead. The idea is that the poor will be looked after, but not elevated. They can have safety (as long as they do what they are told), but not big dreams.
I am not saying this is necessarily Labour policy, but it is the way Labour come across.
In reality, working class people don't only care that their Universal credit is paid on time, they also care about having their own small business, buying a house, being able to get a good job. Yanno, just like middle class people! We all want the same things ultimately-good income, good schools, nice house, safe communities.
NOT that I would vote Tory, but I can see why people did, because the sense with the new style Tories is that they are pragmatic, where as the current Labour lot just seem to see the Working class as an unruly mob who need "educating" and can't think for themselves.