I feel confident in my own abilities to reach my goals, in my own timeline. I have yet to reach fluency in any foreign language yet other people reaching X languages in Y time, just don't bother me. If they are genuinely a lot better I look to what I can learn from them, and that if they can get there eventually I can as well if I persist and focus on my own journey.

I think the crux of your issue, if I may is basing your self-worth on external factors.

The issue I see here is not of 'fake' youtube polyglots but self-acceptance and basing your self-worth on your own values and not in relation to others.

It is also a matter of perspective and attitude to learning.