It's quite ironic how medias use Russian polls when it sticks to their narrative, and bashes them when it doesn't (i.e. Crimean referendum). We should take them all with the same level of skepticism.
I don't think it's about "the narrative" though. I've generally seen these polls used by people who self-identity as against the narrative. These polls are usually posted in the comments section to rebut articles arguing (correctly) not all Russians support the war.