That's the weird thing - even in portable mode, where resolution and graphics settings are pretty much a 1:1 match for the Wii U version, performance is still worse than on the older console. Not by enough that I'd consider the port an out-and-out disaster by any means, but it's certainly bizarre considering that both Bayonetta games had the same settings as the Wii U, and ran at higher framerates (as did Breath of the Wild in that game's portable mode).
Platinum Games did three ports at the same time. Shouldn't be surprising that a third party in that situation gives the Nintendo console the least amount of care, because that's what third parties do.
The kickstarter reached the goal for extra content down the line, so maybe they'll work on a performance patch for Switch during that time too. But either way, the game in its current state isn't so bad on Switch that one should wish for financial failure for Platinum Games.