I think YouTube is bigger (by profit, revenue, customers, or total hours used) than Netflix, Spotify, and Tik Tok.

See: https://mannhowie.com/youtube-valuation

Also see: https://www.cnbc.com/2021/07/28/youtube-is-a-proven-juggerna..., https://www.hollywoodreporter.com/business/digital/youtube-a...