I'm thinking it's the same as mentioned for an email list. In other words, you need $20,000 pumped into YouTube via AdWords etc.. (I don't know anyway to boost YouTube from inside YouTube.)
Anyway, I have no plans for YouTube cause I can't stand videos and video marketing. Nonetheless, I have seen that most people have built Patreon pages via YouTube - and I don't think they got all their people for free - or at least it would have took - along time!
I would not put any money into youtube, most people tend to ignore their ads and just focus on people they like and enjoy content from.
Latest Tech, video game and anime news: https://gaminglatest.com/
I would not put money into YouTube either. I only go on to really view videos and ignore ads.
Gaming Forum - https://www.joyfreak.com/
I think if I was to go seriously to make money on youtube it would be via streaming and encouraging donations with stuff like a roulette of activities, perks from top chat and flat donations. I don't think it is worth it on youtube adverts with how much of thin eye is with the copyright demonetizing.