From my very first training dive, maybe even in the swimming pool, my instructor noticed that he and I consume air at about the same rate.
The one indicator that he breathes air more efficiently underwater is that he is much larger than I am. You can’t tell from the photo, but he is always the tallest one around the dive center, both staff and clients/customers included.
On the other hand, he has around 300 logged dives. While he has perfect buoyancy, I struggle with my buoyancy and still consume air at the same rate. I am still struggling with my frog kick, and I “cheat” and swim with my arms more than I should admit.
The promising news for the future is that an 11-liter scuba tank, starting with around 200 BAR, can last an hour with 70 BAR to spare back on the boat. How long it will last after I achieve half-decent buoyancy, let alone perfect buoyancy?