Just purchased the game. Advice for a newcomer?

I made a post recently asking if I should purchase the game despite the price, but I was unaware that it broke community guidelines. The post was up long enough to get some thorough reviews from y'all and I decided to bite the bullet and buy it.

What advice do y'all have for someone new to the game?

Namely, do you recommend using a controller or K&M? Should I prioritize the main story before or after exploring the map and/or doing side quests? Are there any graphics settings recommended for a solid GPU (3070) but mid-range CPU (i5-12400)?