How much access does Google Sign In grant to Google?


I recently installed Brave after learning about it on a Youtube video and as part of an effort to slowly disentangle my life from Google. Unfortunately, I haven’t found any sites that can match Youtube for content and will continue to use it for the time being. However, before I use my Google sign in to access Youtube on Brave, I want to know what kind of access that will give Google to my activity on/through Brave. Obviously, they will know what I look at and search for on Youtube. What other information will they continue to have access to? I am not an IT expert, but my imagination conjures images of the Google Sign In letting them see all the tabs I have open or my entire search history on Brave the same as they had on Chrome.

What’s the reality?