Yo dude I'm in the same situation. Was a pretty decent tooter in high school and college, made state band in my senior year and now I'm on the comeback trail after 40 years , that's right 40 years. Have to admit my motivation has been my grandson who decided to pursue the horn and wanting to play along with him. I had problems with embouchure, mouth piece etc, even when I was in high school and back then and my instructors claimed I just had to practice more. But now with the advent of the internet information and the freedom to select my own instructors (mom & dad choose back then), relearning the trumpet has been a real joy. My upper register is not back to where it was and my fingering is still a bit sluggish but after 6 months I can see improvement. The most enlightening internet video's have been those of Charlie Porter. Make sure you see "Straight line approach" and " the three compressions". It may feel like you have to digress a bit to adapt to his method of embouchure formation/development and how to attack range issues but this really worked for me. I only wish one of my instructors back in my youth would have taught me these things. I think if you do, you will see faster improvement. Found out I was using the wrong size mouthpiece (I went from a 10 1/2C to now a 3C) you don't achieve upper register by pulling lip corners etc. Give it try. Hope this helps.