Firstly, referencing this link (so that I don’t have to type it all out again >_>). My personal preference is hunting in Friend Safaris but if you’re more interested in one particular shiny rather than finding any shiny period, then soft resetting for things like Hidden Grotto encounters would be the better option, if the Pokémon can be obtained in such a manner. The rest require a lot more concentration on what’s going on in the game and tend to tire me out/kill my motivation more quickly.
Masuda method is technically implemented but can’t be (ab)used right now because the game doesn’t have a way to differentiate between regions. Dunno if suze plans on looking into implementing that or not. Chain fishing also is not implemented though we had discussed implementing it eons ago in dev chat. In 1.2 the DexNav will be implemented, which will make shiny hunting even easier.