(Also this is not counting their sponsorships, merch sales, etc.)

Which is much higher than ad revenue through Google. I know it because I have a friend with a YouTube channel +5mln and he has external team handling these issues. He told me revenue from sponsorships is 4 times more from what he makes from Google and his viewers are mostly from US.

However his sponsorships are really well placed and match the content. Also listening t these ads is not as painful as Linux Tech Tips, so probably he makes more from sponsorships than average.

Yes, so there are YouTube ads and sponsorship segments and people still watch it

I am a full-time YouTuber. This is spot on, only the figure can be much greater than 4X Adsense.

I'd love to talk to you more about this, can I contact you? My email is in my profile, which gives you my YT Channel.

Not a fan of their ads too, but once Linus said that he prefer to take this wildly disconnected ads than to do something related to tech, because it's less risky. They can easily recommend a impermeable pair of shoes but not a specific gpu brand or something like this.

Are sponsorships the parts of the video where the creator will shoutout a certain product/brand? Do they really pay that much?

^ I can imagine the vast majority of their income is through websites / webshops, sponsorships, referrals, etc. If the channel promotes a product there will be significantly increased sales.