Read the privacy policy, they explicitly state they store it. Obviously, because in many cases they need to know who watched that. For instance for their licens

Read the privacy policy, they explicitly state they store it. Obviously, because in many cases they need to know who watched that. For instance for their licenses they need to be allowed to show you copyrighted content. You can ‘pause history’ which means ‘If you turn off your YouTube watch history and have no significant prior watch history, YouTube features that rely on your watch history to give video recommendations, like recommendations on the YouTube homepage, are removed.’ it doesn’t mean they don’t store it. Google stores everything and deletes nothing. If you don’t want Google to keep track of information, you have to make sure they don’t have it and never get it.