of course likes are needed.Should also buy likes. YouTube has to know a velocity relationship between normal views and likes. If you exceed that number they likely would hand a penalty out. For example, in the dog training niche videos generally get 5 likes per 100 views. Video comes along and gets 1000 views but no likes. Very easy for machine learning to say hey this doesn’t match what I know thus rank this lower.
And average view duration.Not only views will help you rank, there is something like channel authority as well.
Do you have any case studies I could look at?Do not buy views or likes, it will just kill your channel