I'll give you Kirby's Adventure being on par with games like Mario 3 in terms of ambition, but by the SNES I view it as no different than what most franchises did with sequels. Kirby was never anything special in that regard. I just don't see how Kirby's attempt to iterate on itself are above and beyond what most franchises were doing at the time by the time you get to SNES. KA1 laid a foundation that throughout the past 30 years hasn't changed all that much and that may as well have been the first game in the series with how is set the blueprint that everything after it would iterate from.
Especially with Super Star. I love that game to bits, but I don't really view it as all that ambitious especially if you compare it to what KA did on the NES. Like adding a couple moves to copy abilities counts as "most ambitious platformers" when we look at what Super Metroid, Yoshi's Island, Mega Man X and DKC did for their respective franchises? It's a great game but it absolutely feels iterative to me. Like ok we have copy abilities and now we give them a couple new moves. It doesn't really feel transformative to how Kirby played or was designed, it just felt like a more refined version of the same combat.
And again, I think Kirby 64 is great, but if our metric for ambition is just "added a new feature and altered the moveset of the main character" then the floodgates open and I struggle to understand what we'd define as iteration at that point.
Obviously definitions are gonna be different from person to person though. I'd call Amazing Mirror a far more ambitious game than Kirby 64, for example.