Google Adsense is an intermediary between advertisers and websites. It operates an auction where advertisers compete to pay the highest for the space (squeezing advertisers) then it determines how large of a cut it can take before paying the websites (squeezing websites).

I suppose you're right, and it does apply to Google acting as a middleman between advertisers and content providers.

I do think the dynamic there is still a bit different from where the term usually applies, since advertising involves three parties in addition to the middleman, not just two -- the above comment was looking at things from the perspective of end users, in terms of where they prefer to watch videos, and that actually may represent a constraint on how much "enshittification" can happen that's particular to this industry.