Does anybody know the requirements to get into the isle of armor at the start of Pokémon sword and shield? I am starting over a new file and I want to catch new Pokémon in the DLC. Even though I already purchased the DLC, I don’t see the armor/tundra pass anywhere in the inventory? What am I missing? Can anyone help me out? I have already unlocked the Wild Area and caught Galarian Slowpoke but it feels like I'm still missing something?

You should be able to go there once you've caught the Galarian Slowpoke and obtained the Armor Pass. Did you talk to the guy again after you caught the G-Slowpoke? Maybe he doesn't automatically give the Armor Pass and you need to talk to him again.
It's also possible you can only travel to IoA from Wedgehurst Station.

Actually... it was a piece of downloadable content that I had completely forgotten about in my account on Nintendo eShop that had to be re-downloaded in order for me to get the armor & crown pass after I did everything in the game at the start.