But are they?

Apple isn't under legal obligation to expose equivalent functionality to userspace. Time will tell if they're moving kexts or blocknig them. My money's on blocking them.

The developers of Little Snitch have confirmed that, at the very least, network filtering would work in userspace via the new Network Extension framework: https://news.ycombinator.com/item?id=22677849

Marco Arment suggests that it's possible that Turbo Boost Switcher might not: https://marco.org/2020/01/13/macos-low-power-mode-redux

And in userspace, you can only do what the APIs allow. Unless there is an API for directly manipulating the CPU Turbo Boost system, you're S.O.L. when kextload is dead