Galarian Articuno
First, fly to the Crown Tundra at Snowslide Slope point.
Don’t move your character and don’t change the camera angle.
Save your game. You should be like this.
Once the result is found, you should go straight ahead to the plateau ahead of the clib. Articuno will be there. Don't fly in another location, or the encounter will be rerolled. If you fail to encounter it or you fail to catch it, you can restart your game, the encounter will remain the same.
You should find Articuno in this location:
First, download the Sys-EncounterBot: https://github.com/Manu098vm/Sys-EncounterBot.NET/releases.
Go in the Hub tab and select G_Articuno under SWSH_OverworldScan.
Scroll to ConsoleLanguage under FeatureToggle and set it to your language.
Scroll to StopConditions and set them according to what you're looking for.
Please note that Articuno is Shiny Locked, but it can be hunted for IVs, Nature and Marks.
Go back to the Bots tab, select SWSH_OverworldScan, click Add then Start All.