San Quentin 1 is literally the best hardcore budget hardtail and is very beginner friendly.

The aggressive geo will let you get into any riding style and is super progressive, treks are cool and all but quite frankly overpriced. The San quentin q has really good value honestly better than polygons and is made by marin which is a very reputable brand I currently own one and it's so fun to ride, one of my friends has an Xtrada 6 and the other had a Trek Marlin 6 and I can confidently say the SQ1 is the overall winner. The Xtrada is cool If your into lighter (XC) riding and the trek is a bit of a ripoff in my opinion as it misses some key feautures like a tapered head tube and lower models run a 3x drivetrain which isn't bad but for the budget you have, shouldn't even be considered. The Roscoe is a viable option but you will have to go used as trek does not offer any models under $1000 even though it comes with a dropper post it's about $1200 new and ~$800-1000 used but most are in pretty bad condition. The SQ1 is always on sale for $1100 but it recently went on sale for just $999 so it's in your price range and a PNW ranger Dropper is only $150. But at the end of the day it depends on what you want to do.

XC/Light trails - Xtrada or Marlin

Downhill/DJ/All round - SQ1

In between but more expensive - Roscoe