$1K is a good price point for some quality hardtails. I don’t have experience with the GT Avalanche you mention, but don’t get too concerned about trying to find the “perfect” bike. Find one that seems comfortable and then ride the crap out of it and don’t look back! If you really get into it, chances are you’ll be looking at an upgrade in 2 or 3 seasons.
A few other suggestions: big fan of 1X gear system (which means no derailleur in the front) and I strongly recommend a dropper post. If you do go with a hardtail, look for “plus” tires – a little wider (about 2.8″) will suck up smaller roots and rocks nicely.