I'm a lot like you. I've posted before about the absolute shitshow that was my OW course, but it didn't deter me. I just wanted to dive and get things figured out. My wife, on the other hand, learned that diving is a scary, out of control feeling or imminent death.
She learned everything that was bad - like "to reach the surface, I must inflate my bcd" - because she was so overweighted, and poorly taught. She did a few dives to humor me, and then gladly gave up for 20 years.
She finally decided to get back in the water after both my boys learned to dive. When she said she wanted to go dive, I took her back to the pool for a refresher and to teach her trim and buoyancy. Now she's the occasional warm water vacation diver.
The problem with teaching yourself, IMO, is the lack of objective feedback. You can think you're doing everything right, but someone else can find things that you could improve (that someone doesn't have to be an instructor, but it helps). A good instructor will have experience with the problem, so will probably have a few "tricks" to get you to improve.
When I did tech training, I knew that my trim and buoyancy were spot on, but day one with another instructor I found out that my head position was off. I'd learned to compensate, but having someone just point that out improved my diving.