It is true that the other way to pursue becoming a "better" diver is through technical training. That will involve underwater skills and bookwork as well...they are not the same as what is covered in the DM course. Going tech also involves equipment changes that you'll have to make that push the overall cost much higher than the DM course. There are some skills taught in tech diving that I think should be part of the recreational curriculum (like trim/weighting techniques, streamlining of gear, fining techniques, gas management, and the value of slower ascent rates). These can be studied to a certain extent without official training, and there is training for these you can do after the DM course if that is what interests you. I have been considering going some tech training, but the more I think about it the more I have been leaning away from it in favor of just going out diving.
Technical Training is AN other way, not THE other way. There's at least a third
alternative: Become a better recreational diver. Take a course like DIR Fundamentals.
You don't have to drink the Kool-Aid (I didn't) for it to be very helpful. (And everything
you learn in it would be helpful for a DM course, and it's a LOT cheaper and a LOT less
work. And dive with experienced divers, and watch them in the water, and ask questions
after. Especially ask "WHY?".