Hi, I have on older trek 3700 with disc up front and rim breaks in the back. I bent the front wheel and found a replacement on Craigslist for 20 bucks.
With all the standards out there it gets confusing.
With disc brakes you’ll want to find a QR rear wheel, not QR15. QR wheels take a standard older style quick release skewer. Higher range MTN bikes take a beefier 15mm skewer(QR15). You’ll want to double check which kind you have.
I’d search craigslist for a decent wheelset if I were you. The stock wheels can bend under hard cornering of rough riding. Don’t spend too much as 26in wheels are considered outdated and you can get a decent set for 40-50$. Most 26 in wheels will take a Shimano cassette