The PDIC Open Water course I took in 1981 did make me feel very well prepared for diving safely. It was very much like watching US Navy UDT/SEAL videos on YouTube. The emphasis was on survival not finesse. Today, we emphasize buoyancy, trim, and propulsion. Back then, class exposed me to lots of harassment in the pool. Open water training consisted of 1 snorkel/freediving session, 2 dives doing skills, 1 dive learning to navigate an out and back course as a team, and 1 dive doing rescue skills. We got yelled at a lot. Very military. 40-hour course.
In the end, I had the confidence to begin solo diving right after class when no buddy was available. The confidence was there right out of the gate, after that I spent my entire diving career just trying to be a better diver.
Now, I'm actually trying to rebuild my confidence after being injured by DCS which left me dizzy for 2.5 years and without the use of an eye. I went from the training director of an agency and a cave instructor trainer evaluator to feeling like recreational dives are big deals and silent bubbles are like enemy snipers.