i agree with most if what you said but add a couple things.
One, the Republican complaint about identity politics and dei contains a kernel of legitimate criticism: the left, not just the dems or political class but the whole left, has mostly become concerned with elite issues* In a way twas always thus, but in the past the left elites *also* genuinely cared about folks who do real work for a living (or would if they could find it).
Two-there is a path forward. If enough elites can set aside their shit for a minute, we could probably put together a compelling coalition that would work against racial, sexuality, etc. exclusion, and care about the greater world that sustains humanity, and makes sure everyone is provided for with dignity.