I pay for YT premium and Ads are still my #1 complaint about YT.
Partly this is by design, where it seems to decide that a creator having a "merch" ad integration doesn't count as an ad. Which might be understandable (but still not what I want) if merch meant creator's face on a mug, but it also includes products where a home fix it channel will have an overlay of products from Home Depot which is literally just an ad with no caveats (an overlay that obscures the video on Chromecast, it's part of YT UI not embedded in the video).
Though I guess I'm also unclear how often I see that because Premium is buggy and how often it's intentional. Ever since they made YT on Chromecast an "app" it's been a disaster of account state bugs where it also keeps trying to enforce safe mode (which blocks half of everything, including practically any music video) because it says it's not logged in even though I'm trying to cast from a phone that is logged in.