>understand almost everything said...
If by 'almost everything', you mean stuff that a non native English speaker could have understood anyway, then yes.
If by 'almost everything', you mean stuff that a non native English speaker could have understood anyway, then yes.
The vast majority of English learners are not able to caption most Youtube videos as well as the current AI can.
You underestimate the amount of time required to learn another language and the expertise of a native speaker. (Have you tried learning another language to the level you can watch TV in it?)
Almost all native speakers are basically grandmasters of their mother tongue. The training time for a 15-year-old native speaker could be approx. 10 hours * 365 days * 15 years = 54,750 hours, more than the time many professional painists spent on practice.
A weak speaker may use a cognate, idiom borrowed from their native tongue or a similar wrong word more often. The translation app produces completely illegible word salad instead.