Well Overswarm loves to projectile camp. So first off try and keep him in fsmash range, don't go in, the reason here is if you spot it quick enough u can smash him before he gets projectile off. Honestly he won almost every match I saw him play this way, so not sure how his up close game is, prolly wanna roll away instead of sidestepping, i know he loves to down smash which hits even if u sidestep. In the air ur bair has decent priority on his fair, but when he's landing don't be underhim, contrary to most characters u wanna stay in front of ROB since all his forward attacks are relatively short and weak, especially in the air, that bair is crazy.
If you have to approach you prolly gotta mix in delayed attacks, for instance don't grab as soona s possible, delay it for .5 seconds or so, he's so quick on sidesteps gotta throw off his timing.
Side note- How do u beat olimar(tether grab gave me so much trouble, nc echo was able to beat me kinda easy grab me mid attack) and stop diddy's banana combo's? These are 2 characters I can't seem to deal with wolf.