Advice For Learning Every Scale And Key

a long time goal for me has been to know how to use any scale in any key on the guitar, any advice on where to start?

Question About Legato Etude Lesson

i have been playing guitar for about 4 years. my legato technique is pretty good but it feels sloppy. while using this video to learn and perfect it i realized that my left thumb posture on the neck was incorrect and while fretting the lower strings i would turn my left hand outward. now that i have corrected the posture and technique i feel much slower. should i continue to play with the incorrect technique or keep practicing with the fixed technique even though its slower?

Link to lesson:
https://www.guitarmasterclass.net/solo-guit...o-etude-lesson/