I've had the same problem as you for a long time now(not being able to practice against people enough), recently I've been able to get my friends into smash more but we only play once a week together if we even practice that much. CPU's are pretty stupid in general and after practicing against them for a while and then trying to play a person they just screw you up. I've been using my little brother as somewhat of a practice dummy recently to practice new moves and getting off combos against a human opponent so if you could find someone who would just do what you tell them to then you can have practice against random di's otherwise maybe taping/rubber-banding a spare controller's analog stick one way so you can work on something that's di'ing even if it's the same direction and it will walk off the stage. Maybe there's some mod for pc where the cpu's di, but if you have a pc that can run smash at 60fps and good internet then you can go and play people on dolphin's netplay feature, and if that's a possibility, I'll play with you, my internet is kinda crummy but it works decently enough with someone who has good speeds, or maybe when I go to play with my friends we could all play you online to give you some more variety in your opponents.
