How to configure a view accessible on user's profile only by that user I have a view listing the nodes a user created on /user/{user}/mycontent.

How should I configure the view so that other users won't have access it?
If you don't want them to see their own content instead of the user which profile they are currently viewing, you need to add a contextual filter

skip to 8:52 and watch Views Relationships and Contextual Filters

Note: this is for drupal 7, but I imagine the drupal 8 views look the same.