And I was postulating they'll invent that shortly before Picard's adventures. There's nothing "handy" about the device in the DSC/TOS/TAS timeframe yet.
Voq needed Tyler to donate a body. Few would be likely to volunteer.
And while multiple techniques exist for creating android bodies in the TOS timeframe, we get no hint that "someone's physical form" could be created with the tech that makes uniforms for Burnham or burgers for Number One.
And it explicitly is there in the DSC/TOS/TAS timeframe. But Pike probably had good reasons to think that taking Vina off the planet and having Boyce wave his trusty dermal regenerator over her pretty face would not be doing Vina a service.
I don't quite get this. McCoy was adamant that he couldn't do whatever he did if not for the Teacher. That the device didn't stay hooked on all the time but was of a fire-and-forget type doesn't mean that Starfleet doctors would be capable of reattaching a brain - heck, even McCoy lost that ability with the "forget" bit.
Working brains like that is an alien ability explicitly not available in the DSC timeframe. Whether it becomes available in the post- "Spock's Brain" one can be debated (apparently, McCoy couldn't take another dose of it), but that wouldn't much concern poor Vina.
As for remote control of nerves, and muscles via them, I've tried it out a couple of times. It wouldn't have fixed my spine. Or, say, Christopher Reeve's.
Timo Saloniemi