• Youtube is consumed A LOT on the website, including some people using the mobile website (not the app) to keep it playing in the background (duh). This only compares average time on app.
• It could also be totally skewed, if let's say 100M people spend 2h/day on average on Youtube, and 1k (a tiny amount) spend 2.5h/day on average on Tiktok, that'd be already good enough to say "average time per user spent on the apps is higher for TikTok".
I haven't read the report, but wanted to point out these two warnings. As we say in Spanish, the easiest way to lie is with statistics. And of course any half-decent PR person will take any numbers and blow it up into a headline, so tread with caution.
(Absolutely not wanting to discount on Tiktok, which has been growing at an incredible rate, just wanted to say that the wording on how exactly they are "winning" sounded a bit contrieved).