abusing cape and blocking works for me. Olimars tend to do spam smashes. the more they use it the weaker it gets. So try to play defensively. pressure him with fireballs, space with cape, and watch out for dashed up smashes, its strong and real fast. Once he's off the stage, Bair him to death and make sure u always cape him. Idk i never really have problems Olimar.
Then you obviously aren't playing any good Olimars.
Olimar is Mario's 3rd hardest match-up
Cape spamming doesn't work. sure it might reverse his pikmin but most Olimars won't care considering they might do 10 damage and fall off and then they are his again and even if they do care about damage it only takes 1 whistle to get them off him and during the start of the whistle he gets super armour
Spamming fireballs isn't even that reliable considering it only takes 1 red pikmin Fsmash to **** up your whole day
Bair is not that good of an edge gaurd move unless they are at high %s considering your opponents should be DIing Up. Speaking of Bair it's not even that good of an approach on Olimar considering he'll just shield grab you
also...what is this make sure you always cape him thing? get him below the level and sit on the edge. That's it GG he's dead