Both of them can be done shitty-ly now. But to do it with quality that even healthy people will voluntarily get it? That would need several breakthroughs.

We can stimulate some neurons now; to be able to stimulate enough neurons to do either of those in good quality will be hard. Cutting edge stuff can stimulate ~1000 neurons (only monkeys not even humans) but the human optical nerve is more than a million fibers. So we probably will need 3 orders of magnitude improvement and somehow do it in humans safely.