Oscar is not really a master of over takes at this point, as far as I can see. The move itself is only one part of it. Everything else around it, the approach work to manage the car into an overtaking opportunity while keeping tyre temps and life under control has work to be done. But it is all stuff that is gained with experience. He certainly looks good at taking an opportunity, but he needs all of the approach work around it.
But certainly around qualifying Oscar is not only consistently behind Lando, but also consistently close. You shouldn't really look at one side of the equation without the other, but plenty will as it's a nice headline (Here's looking at you, Lucky!). The average gap in Qualifying since and including the Miami upgrade, is .123 seconds. The median is .08 seconds. From that perspective, qualifying performance looks very close.