Is ONE PIECE episode 1028 filler?
Canon No, episode 1028 of ONE PIECE is canon.
#1028
Surpass the Emperor of the Sea! Luffy Strikes Back with an Iron Fist
四皇を超えろ ルフィ反撃の鉄拳
Aired 7 Aug 2022
Mochibayo compiled this list from MyAnimeList's labels, because MyAnimeList's episode data is not reaching us at the moment.