Hard to say for sure, since YT uses shared Google infrastructure, and effectively cost of some things can’t be calculated. (Basically it’s much cheaper than you or me can do ourselves).

But from what I understand, they burned money for many years and only very few years ago became profitable. But in some sense YT doesn’t really have to be profitable - for Google it’s more important to prop search itself, then to make money on YT.

They don't tell about profitability, but revenue was $15B so chances are they at least break even.

https://www.theverge.com/2020/2/3/21121207/youtube-google-al...