The shining/brilliant whatever it's called method of shiny hunting in Sword and Shield kinda sucks. It's like the DexNav from ORAS but worse. The shiny rate is halved for brilliant pokemon at max rank, which takes a while to get to, while also doubling the brilliant rate but since it's based on the overworld mons which were hastily added to the game, the rate of seeing one is still pretty important. Getting to max rank is also time consuming making me doubt the time gain if you're hunting for a single shiny of that mon.
Overall it doesnt feel that different from just random encounters hunting.