Sorry to burst your bubble but users literally do not care "how native it looks" other than the vocal minority online. Never ever heard any non-technical user complain that Spotify does not fit in.
They're willing to accept a certain amount of "specialization" for things they care about deeply / use all the time / demand unique approaches, but people like things to look and behave the same when they're pure utility. Which most things are.
People don't complain about Spotify, because (1) the design feels and performs like something Apple would design, and (2) music is something people have feelings about, and so expect differentiation.
But Apple doesnt? Why else would they throw away their current design language, and invent something new ("Liquid Glass").
They're rolling it out across their entire product catalog, so more consistency if anything.
Take Slack for example with its fancy menus, not even close to what Apple uses. No feelings expected there. Let's not talk about Google apps, which live in its own UI world.
This assumes they have a choice between equivalent apps that OS-integrated and one that are not. Many times, they don't.
Anecdotally: while some people don't care about consistency in the art they put on their walls, most do.
Slack is included in the "apps that you use all the time" rule. Also in the "apps you don't have a choice about" rule.
(Edit for spelling and wording)