Obviously they are since i got a youtube premium feature the other day that gave me a button to skip a sponsored segment and it's most likely an ai that said the segment starts here and ends there from learning the sponsorship patterns.
That data is also publicly available (of course), so a model could be trained on it. I'd love to say I'd doubt Google/YouTube would ever do that, but at this point nothing would surprise me.
As a other premium user, trust me that is not the main reason I use it, it's entirely to get rid of ads on mobile. I use the feature occasionally on mobile too but on desktop I use sponsorblock and it's wayyy better both from an accuracy and user interface standpoint.
Sidenote: I also am on a plan that my parents pay for, though I used to pay for it myself after getting it for free for 6 months and I couldn't go back to the ads