no one likes taking that 60, but the more you see that as your punishment for messing up, the more motivated you'll be not to mess up. don't change your approach to the game based on a technical limitation because technical consistency comes with time whereas bad habits die hard.
eh, just sorta walk up there and bait him into jumping up and react accordingly. if he just keeps double jump stalling, you can slip a dsmash/dair/edgehog in there, but usually the marth just wants to pop up onto stage and grab you so just watch for it and be ready to shield if he aerials or shine -> grab if he just wavelands onto the stage into grab/shieldgrab.
eh, just sorta walk up there and bait him into jumping up and react accordingly. if he just keeps double jump stalling, you can slip a dsmash/dair/edgehog in there, but usually the marth just wants to pop up onto stage and grab you so just watch for it and be ready to shield if he aerials or shine -> grab if he just wavelands onto the stage into grab/shieldgrab.