It was very obviously happening in replies, which is different from "For You". The reply system had a different sorting algorithm that AFAIK prioritized verified accounts even before Elon came along. It was very visible now that the "pay for verify" system was available where you'd have a viral tweet with a solid wall of verified replies for pages before you'd see the far-more-popular unverified replies. The quality hit was bad enough I wouldn't be surprised if Twitter is quietly turning down the weighting of Verified in replies, because it's so extreme.