Even if you don't get much of an opportunity to play with others, there's still plenty you can practice on your own. With Luigi, wavedashing is going to be HUGE. If you can't wavedash 100 times in a row without jumping or rolling, that's still something you can focus on. And if you can? Start messing around with different wavedash lengths. Try going to Pokemon Stadium and hitting specific points on the map with different length wavedashes. Wavelanding effectively really speeds Luigi up too, and can watch Abate and see how quickly he slides around the map. Obviously experience against other players is incredibly important, but between L-canceling (including after hitting an enemy), Out of Shield options (aerials/ wavedashing oos, upsmash, up-b), and comboing cpus, there is still a ton that you can work on by yourself. The more work you can do on your own, the more you'll benefit when you do get time to play with other people because you'll have a ton of new tricks to try out, and you hopefully won't be dropping games because your execution is off.