Does the input lag make a difference or am I just being crazy?

Coming from Smash 4, this game sometimes feels either really fluid or really clunky. It's as if sometimes the game fights with me on what I inputted/what it wants to do. Sometimes, I get extremely trashed but it seems like everyone else doesn't really have a problem with it. Am I just bad? Or am I just struggling to get ahold of the new feeling of this game while everyone else already adapted?