While prepairing for JEE advance, you can refer same syllabus or topics which you referred during preparation of JEE main. As there is manority syllabus is same for both JEE main and JEE advance. Only difference is of depth. In JEE advance you required more depth and thorough knowledge of any topic. In stead of youtube you can check videos in unacademy. As they have created videos of almost every topic. And also take video lectores every week so you can solve any doubts directly there only. In every video in unacademy they start with very basics and then go through at depth. At the end of lecture you get assignments also for self evaluation. So unacademy video lectores are more preferred. If you really want to go through youtube then nust check for any specific topics and check out videos. Check the numher of views of that videos. Also check the comments section from there also you will get an idea.

So from my advice , you can check videos based on topics. As there can be possibility if one channel has explained one topic so nicely, then for other topic they are not as much efficient.