Assuming we're ignoring custom moves I personally don't consider Dr. Mario or Ganondorf "good" characters, even if I might do well with them online.
I'd possibly throw Falco in there as well.
Too many limitations compared to the top of the cast, Ganondorf is an incredibly lazy port from Brawl with a few minor buffs and holdovers from Melee that don't make any sense for his current iteration (i.e grab range iirc).
Dr. Mario feels too sluggish and he's too easily gimped with not really enough of a power increase to make the change worth it imo.
Falco can whiff his USmash after connecting with it due to it being multihit, his jab string is awful due to the delay after the third hit and they nerfed his lasers to the point of almost being useless (but atleast they buffed them to travel faster, that's... not really useful at all), the hitbox on his side b only covers like 70% of it or something, DAir got ruined.
That's just the characters that I feel like I have something of an amount of experience with though, I don't think I'd consider Olimar, DK, Marth or Zelda "good" either, they're definitely not anywhere near any of the characters that are actually good in the game anyway.