None, don't watch YouTube videos
I used to say that a few years ago, but now a tiny proportion of what you and I would call 'just YouTube videos' are proper programmes.
For example, the GCN Epic Ride in Andalucia linked in this thread is a nicely produced cycling travelogue.
As
@ColinJ alludes to, the trick is sorting the small amount of wheat from the much larger amount of chaff.
I like most things made by Matt Stephens, who now works for
Sigma Sports.
He does sometimes try too hard to be funny.
Some of his stuff is no more than a puff for the brand, but his series of rides with cycling personalities are worth a watch.
He also did some good videos on the routes used for the cycling championships in Yorkshire.
Those videos appealed to me partly because I've ridden a lot of the roads.
Put 'Matt Stephens' or 'Sigma Sports' into the YouTube search box and you may be pleasantly surprised.