>>57961887
I honestly don't think there's a silver bullet that will fix him short of meme answers like Pure Power. I thought about Geomancy but he unironically lacks the special movepool to get much out of it. Any Steel type would still wall him.

For a multi-stage solution I'll say Drought, Fire Blast and Growth. It's crazy we don't have a Grass type Drought mon yet anyway, may as well be the most abused Grass type starter since Meganium. It'd be nice to have a Grass type that can actually use Solarbeam.