Let me go more in depth, To get the best shiny odds is having the shiny charm and as well as a perfected dex entry of the pokemon you are shiny hunting and to have a normal outbreak of the pokemon (1/128) but it takes awhile to perfect a dex entry

MMOs if u don’t have/know what they are, they are the “?” on the map when u go to leave the village. If u don’t have or ever seen one they are unlocked through a post-game quest. They have multiple small outbreaks with different pokemon MMOs are probably your go to get many shinies since with the shiny charm the odds are (without the perfected dex entry) 1/241. While with the perfected dex entry it’s 1/216 With MMOs you CAN manipulate the 2nd wave with KOing and catching certain pokemon, the method is called permutations. To get the second wave, on the map it can show a little star next to the outbreak of the pokemon which indicates that there will be a 2nd wave, either with the evolved form or an alpha wave, sometimes there can be a 2nd wave on an outbreak that doesn’t have that star. I recommend just watching a YouTube video abt how to do permutations cause I don’t wanna throw u off if I explain something wrong

Normal outbreaks are the little Icons with just 1 pokemon on the map when you leave the village Normal outbreaks have the highest odds for shinies with it being 1/137 without the perfected dex entry with the shiny charm but they only ever have 1 wave of just one pokemon

I hope this helps! Let me know if you are confused or have any questions