Hi!
I am Nataliia Zharkova, a former world record holder in no fins freediving. I dove to 70m depth bare foot and returned safe and sound! I used to compete in all depth disciplines and I want to say that diving shallower depth without fins is somewhat more challenging that going 100m depth with a monofin!
Think about it - another name of no fins discipline is “unassisted”. This term is used rarely but it very descriptive. Diving with fins or even more a monofin gives you an “assistance” - the powerful blades with all its surface to create propulsion. Diving without it you have only your body - your feet and your palms to move your body weight through the water.
I believe I became good in no fins diving thanks to my swimming background. Numbers of drills I’ve got to practice during swimming years became very useful in mastering kicks and strokes, movement coordination and in building up aquatic awareness - all key ingredients to successful no fins dives.
Now I am willing to share my experience with you.