Would you take a painting course online if the teacher could not look at what you were painting and make suggestions? Would you take a course in writing online if the teacher couldn’t read what you were writing? Would you expect to learn to play piano by looking at web videos?
If you seriously want to be a better singer, someone with expertise has to listen to you while you sing and give you feedback. Better still, you need to find someone who not only sings well herself but also knows how and what she is doing while singing. For the most part, the people on YouTube don’t have a clue. They are there so they can make a lot of money from eager beavers who don’t know any better.
It is flat-out impossible to learn to sing exclusively from watching a video, no matter who makes it. You can learn about singing, as intellectual information, but you can also find that in a number of books, especially recent ones. If you consider just singing songs in any old way as a path to learn to be a better singer, you can waste a lot of time and lose a lot of money and never get anywhere at all. Please, don’t spend your hard earned cash on websites and YouTube videos. Go find a live human being and study until you get better and know why.
Remember that we in the USA are living in a very strange time when people are famous because they are famous. Being a “celebrity” requires nothing except that you got lucky and became a “brand”. Being good at something always requires spending a lot of time with it — years, not months. Being an expert requires about 10 years of diligent work even if you are very talented. Doing something that is a physical skill (which singing is) requires that you do it under the guidance of an expert. Being an expert ought to mean that the person teaching has both training and life experience and, in the case of singing, they should sing well. The only exception to that would be when the teacher has had some kind of injury or illness that precludes them from sounding good, but it should be assumed that that was possible in the past.
Remember, common sense. If it feels bad and it sounds bad and it’s very hard to do and it doesn’t make it better, it’s WRONG.