The guy I learnt from was a world top twenty player and had his foundations drilled in China. When I first went to him, I was pretty much like how you play with no clear idea of the court positioning, techniques etc. My backhand probably was slightly better than yours though because of a better grip. I did a lot of practice at home with shadowing, just trying to drill correct foot patterns. In social games, I didn't care about winning the point or match. It was far more important to get the footwork pattern correct and in between points, I would try and shadow the correct footwork again on court. So, I would worry more more whether I could do a flying step. I was a mess for the first three months but I had already accepted this because I told the coach I wanted to have good basics. Six months later my game play was improving loads. 8-9 months later, I was being invited to singles games by other local HK coaches and winning or at least getting to later stages of tournaments.and he has ranked quite highly in England previously for MS/XD
Your advantage here is your motivation (same as me) and the internet (which I didn't have).