For 6 IV Ditto, you need to rescue him from a raid, and this may happen in a certain location. For new players, Buy Cheap Shiny Pokemon (https://www.pkmbuy.com/) is a good way to get a shiny one. There is a raid point in the rocky wilderness area in a wilderness area, hidden in a small corner. From the nursery, walk right to the bridge, you will see it behind the tall grass. This is where the Ditto team raided.
When you shoot a purple beam from the raid point, you will have a Ditto. The star ranking in the upper left corner determines how many perfect IVs it will have, so please look for a 5-star raid. If it has five stars, you will get at least 4 perfect IVs, but there may be more.
This is the best way to get 6 IV Ditto breeding in Pokemon Sword and Shield. It may take some time, but there will be gains if you stick to it. If you are just a casual player and don't have much time to invest in the game, then you can Buy 6IV Shiny Ditto (https://www.pkmbuy.com/Items) in a reliable store, which can help you improve the efficiency of the ranger and better enjoy the fun of the game.