You've conveniently ignored the part about Labour now being more trusted on the economy.
That's not a small cliffnote: for Labour that's a huge breakthrough and speaks volumes about how badly voters think tories are dealing with it. Miliband's tenure never enjoyed that reputation, and Corby's was dire on that front.
Starmer's personal ratings also suggest voters see him as much more of a PM in waiting than Miliband ever was, and lightyears ahead of Corbyn, whose personal ratings were dismal even when the party was polling relatively well. Again, this is not Corbyn v Johnson round 2.
And no, no matter how much mumsnet thinks the rest of the country is obsessed with self-ID, it really isn't. The tories will try to use it as ammo in an election and maybe then it will get traction, but right now the data shows it's waaay down on voter priority lists.
(FWIW I don't think Labour will get a landslide, just enough to secure a coalition. The economy will be the defining election issue and the tories don't have answers for it. Culture wars don't work when you can't pay your gas bill.)