Policies don't mean anything when you're not in power, they're not policies, they're pipe dreams for the future if you're not going to win enough seats. Same as we found out with Brown, Milliband and Cobyn twice. The last person to have a manifesto and some policies before being elected (over the current party in charge), which he got to implement was Blair, but that was ~25 years ago.
There's zero point in drawing a firm line in the sand on some of the major topics, when you can draw a more informed and thorough line in 1.5 years time, that will be the time to judge. Sure, you can comment on these topics, but a lot of them you can move around to suit the current situation, no problem with that. One of the only firm lines labour have to draw (unfortunately) is that they won't rejoin the EU or have a second referendum, as this could end up in a loss, and even more Tory carnage.
Policies will be in the manifesto, and then when he wins he'll likely enact the vast majority of them. I don't expect him to enact them all, like I wouldn't expect anyone else to. I won't agree with them all either, and I'll flag those up if they're major, if they're minor then I won't be fussed either way. My bet is I'll be happy with ~70-90% of it, like I was with JC, Miliband and Blair's. This will be better than the 10-30% or so Tory policies I expect to think are ok (from Sunak anyway).
Of course, there will be some changes to what is carried out v what is in the manifesto, as the world will change, just like it always has. The number of changes should be expected to be proportional to how much the world/ current situation changes.
I'm centre left, as far as the makeup of UK voters goes. I just want a fair balance for most, which also supports those who need it most. You might see that as no policies (it's not), but even It it wasn't, it's a better policy than promising the world and losing to an absolute bunch of cretins who will make things far worse for those who need the most help.