Yeah but you can do appkit with swift without having to use objc

That's still a big chunk of new code you need to write only to throw it away a few years later. Even with just a handful of developers for a year or two that's still millions your throwing away, meanwhile you're developing this Electron thing for the Mac anyway so using that for a few years instead has zero cost.

Appkit isn't going anywhere and you can migrate piece by piece to swiftui