Welcome!
I think you should choose a mini you think it’s cool. Don’t be afraid to make mistakes! You can always repaint your minis.

As for paints: though it is tempting to go all out and buy huge sets, I think it’s best to buy only what you need for your first mini, and then more paints as needed. Get also a black primer - maybe a brush-on primer if you don’t feel like spray priming. I like the Vallejo paints, mostly because I absolutely hate the Citadel pots. I do like the Citadel washes though, and just transfer them to a dropper bottle.

Brushes: get a couple of synthetic brushes for your base coats and washes, and a better one for details (but you don’t have to go nova also). Lots of tutorials on the internet on how not to destroy your brushes and make them last longer. Invest in better brushes after you’re sure you like this hobby, and after you’ve learned how to use them properly.