Your cut looks fabulous to me, if you were in Los Angeles everyone would be asking you who cut your hair. It looks like a nice 60's retro short bob, bet you get a nice high top fade in the natural state. Furthermore, that cut will grow out to a nice bob. I would stick with that stylist for cuts, she gave you a great grow out cut.
Now on to some of your other points, sorry the hair journey has been so turbulent for you. I too acquired tree splits, and mid hair line cracks from baggying when I first started. Now I know how to maintain a baggy routine for fine hair, so I enjoy progress from it.
Again, I completely understand the frustration of drastic hair length differences. My hair is much shorter this year than last, because I have been trimming as areas that were bald get a little longer. Sometimes I am a little down when I think about the loss of length and wonder if I made the right choice. But I enjoy the luxury of thick healthy looking hair like yours.
All I can do is hair sister with you on this one, and let you know it was the baggying that caused the tree splits. Fine hairs are very sensitive, and can explode from all the moisture in the baggy technique unless your reggie is on point, and you baggy with the right products for your hair at that moment. I have witnessed this on many boards. With our delicate hair, we just have to accept the fact that some setbacks while getting our reggie together is a part of the journey. Since you are a fast grower like me, I bet summer will get you to a sexy neck length bob, and you will feel better.
I know you want an individual regime, but really none of us can see your hair. I think swimming, shampoo, and tree braids grows my hair, but I wouldn't baggy while swimming often. I use heavy sealers all year long, and grease when I swim. Learn to use the search engine, there are several threads on swimming, it shares what type of cap to use, and everyone shared what they put on their hair over time. Some were successful with conditioner, and others like myself used grease or wax. God's speed on your journey, I know you can do it.