Kinda.
Just about all RNG employed while generating new pokemon in Sword and Shield has been reverse-engineered, but they all employ non-exploitable cryptography-grade RNG supplied by the console itself, except for a single situation: re-rolling the contents of a single raid (which is to say, looking at the pokemon and advancing the date without starting the battle).
With CFW, you can extract the save and use a PkHex plugin (
https://github.com/Leanny/PKHeX_Raid_Plugin ) to see how many times you will need to re-roll a raid before a shiny will appear, making for an easier process; you still need to manually re-roll the raid the specified number of times, though. Or you can fight the current raid pokemon and throw a new wishing piece to get a completely new seed if the current one will require too many re-rolls before spawning a shiny.
The thread Austin showed in the video was about extracting the saves from a vulnerable, but not currently hacked, console without leaving any trace or indication that this happened, BTW; nothing to do with the exploit itself.