So much this. Is the Switch really that insecure that there are ROMs floating around of this already? o.o

Yes, there's already emulators able to run the game (if barely and not really playable)[1]

[1]: https://www.youtube.com/watch?v=8EdJ2dfL9S8

Well that's a 2500U, almost nothing but the simplest games are playable on that chip.

https://www.youtube.com/watch?v=lhdDfcEkxXM

This one looks more playable albeit still very choppy.

There was a hardware boot ROM exploit a while ago that enabled arbitrary code execution, and I am presuming that is allowing the ROM dump.

Judging by the output folder structure, it was likely done with KillzX's Switch Toolbox

https://github.com/KillzXGaming/Switch-Toolbox

Seconded. I'd really love to know more about how it's done.