The "Switch 2"s official name and release date is currently unknown. The close date will be extended once the release date is known.

A "Switch 2" is any new hardware revision with improved on-paper specifications, even if it still plays the same set of games. Knowing Nintendo, they might call it "the new switch", "switch plus" or "switch pro". The "OLED Edition" switch would have met these criteria on its release, due to the improved screen specs.

"hacked" means being able to run homebrew games - as an arbitrary concrete example, it must be able to run a Chocolate Doom port https://github.com/lantus/chocolate-doom-nx . Running as javascript or wasm within the web browser doesn't count, it must involve arbitrary native code execution.

An unreleased or one-off hack performed by a security researcher doesn't count, it needs to be a publicly available hack, usable by hobbyists. Hardware hacks such as modchips still count.

"Flashcarts" that are only capable of playing existing commercial games do not count as homebrew.

Disclosure: I am myself a security researcher, who has contributed to the switch homebrew scene in the past. There's a good chance I'll end up working towards hacking the switch 2, too.