I would suggest buying a load of different dried chilies as they're a common base to a lot of Mexican food and difficult to replicate. Also most meats are slow cooked, so if you haven't already got one a slow cooker or instant pot will help.
Elote - Roasted/Grilled corn with Cotija cheese and a spicy mayo/sour cream sauce. Sauce is usually dried chili powder, mayo, sour cream, coriander and lime juice or some variation.
Birria Tacos - Basically a slow cooked beef stew, pull the meat, put into the taco, dip the taco in the stew then fry it in a pan.
https://www.mylatinatable.com/authentic-mexican-birria-recipe/
Sauces/dips -
Roasted tomato and pepper salsa roja w/ mango and habanero - been making this as part of a dish at work and it's great. Roast 1-2 habanero, 3 red bell peppers, 5-6 medium tomatoes, let cool and remove the skins. Blitz with the juice of one lime, 2-3tsp salt and a handful of coriander. Then finely dice 1 red onion, one mango, 2-3 medium tomatoes (seeds removed), one green bell pepper and mix it all together.
Guac -
https://www.youtube.com/watch?v=tHVzFLtvbGQ&ab_channel=InspiredTaste
Salsa Verde -
https://www.mylatinatable.com/authentic-mexican-salsa-verde/
Pico de gallo -
https://cookieandkate.com/classic-pico-de-gallo-recipe/
Pipian -
https://www.cauldronfoods.co.uk/recipes/pipian-verde-with-pan-fried-tofu
For supplies:
https://www.souschef.co.uk/collections/mexico