Privateer 161

This won't cost a ton to swap out parts as they wear and break while they kept the Xt shifter so that you can double shift in both directions, whereas...

Another random idea, though not easy to find necessarily, is a Privateer 161. Good STA for climbing, built to be affordable and long-lasting for enduro racers, has some features like external cable routing that may be useful for quick and easy fixes during races. Or you could always look at something like a Commencal Meta AM, 160mm rear travel isn't a huge upgrade but they're affordable, easy to find used, and for your budget you could probably find a used frame and (somewhat) bling it out if you wanted and could find the parts. Ultimately, I guess it's just about priorities though.

The Bottom LineThe Privateer 161 is an aggressive, capable Enduro bike with exceptional pedaling efficiency and notably progressive geometry, at an unusually attractive price.