I do not use gmail but I have noticed anecdotally the frequency of people mentioning this issue here has increased steadily over the past few months for what it's worth.
Something else I have also noticed are the comments people leave stating that they don't like to unsubscribe, rather they report the unwanted email as slam and leave it at that.
So people are reporting tons of emails as spam instead of just unsubscribing
That's true. But I doubt people would report their bank statement emails as spam. I think something's going wrong with a new update in the backend...