I’ve tasked myself with trying to get a full shiny living dex this year, making a ton of fast progress using gen 7 RNG manipulation. I know some folks see it as cheating, but I’m only getting these for myself (and anyone that wants one for themselves!), and I enjoy the process of it!
Currently, I’ve got CFW set up so I can follow any of the guides on pokemonrng.com. I originally started and got a lot of these without CFW, and I think blisy on YouTube has some good videos on RNG without CFW. Here’s a playlist of his guides on sun and moon specifically.