I suppose I want the OLED one. Is it ok to go for the 64 GB version or should I go for the higher storage tier? It has expandable storage yeah? Or is that not reliable or fast enough?

Depends on what you care about. If you can afford more onboard, it’ll be faster than an SD card. Some people say to buy the smallest one and install your own SSD separately, but personally I preferred to just get the first party one.

Also, what’s going on with the pricing? It’s just obviously better to buy direct. Why are people trying to sell it on Amazon? I get people trying to sell on eBay and Craigslist but Amazon? What’s the deal there?

No idea. Maybe those are resellers or scalpers? Just buy it from the Steam Store.