The ads come at different entry and exit points for every user.
They’re not referring to the YouTube ads, but the “let’s take a minute to talk about today’s sponsor nordvpn that I used on my trip to Antarctica.” This is a part of the video file itself, and it starts and ends at the same time for all users.
Bro, which company expected you to do a take home assignment that took 2.5 months? Name and shame the fuckers.