Yes. Every payload you launch uses it. They had two ShofEL2, and another unnamed one. ShofEL2 is also known as Fusee-Gelee and is what Atmosphere, SX, etc uses. This exploit was discovered by at least 4 people independently (F0f, KTemkin, Team-Xecuter, and the anonymous leaker who posted it on paste bin). The other unnamed exploit isn't really useful unless you already have control over the system and it lets you patch the boot rom before going in to sleep mode. Both exploits are documented on switchbrew and are the first and fourth exploits in this list. https://switchbrew.org/wiki/Switch_System_Flaws#Hardware
Yep tethered coldboot is what it was and what we've got. If you want untethered, get a modchip fitted. This is as good as it's gonna get, and honestly it's great.