I get and understand the premise of the show, what episode do I have to watch to not see filler and not watch 15 hours also?
One Piece Filler List | The Ultimate Anime Filler Guide
But I mean...the series has been running since the 90s. There's really not all that much filler, any way you do it you'll have to put some time in.
By the time you finish the Arlong Park arc (somewhere in the mid 40s of episodes I think) you should know if the show is for you or not.