Since you're a fan of getting information from YouTube:
Social media (which YouTube effectively is and twitter certainly is) can be a good starting point for getting information but it should never be regarded as the end point. For starters it's worth checking the veracity of any information by looking at the sources supplied, and if no sources are supplied then alarm bells should already be sounding on the validity of any claims. Secondly anything you are exposed to on these platforms is heavily targeted based on algorithms that are shaped by both what you engage with and what you choose to follow. For example: while I had already seen both of the above videos I chose to find them by searching "The Great Replacement" in the search bar and all of the videos I was shown were debunking the theory - I am sure that if you searched for it yourself you would end up with a bunch of videos saying that it's true.
Social media is great, I am practically addicted to several different platforms (including YouTube and twitter), but it is specifically designed to create an echo chamber where being exposed to ideas that challenge your own world view is impossible unless you go looking for it. That goes for people on the left and the right, neither side is immune.