Surly Karate Monkey Fork 1-1/8" Disc Only Black | Bikewagon

Surly makes a rigid black fork that would work great. You'd want to take some measurements to make sure it won't mess with your geometry. Changing the fork is something you can do but with new forks you typically need a the shop to measure and cut it to length as well as uninstall and reinstall the headset that goes to the fork( i forget its name). If you want to drop some weight and rotational mass I'd get a lighter wheelset that supports tubeless set up as well as lighter tires that do the same. If you aren't hitting rough trails you don't need a chunky tires. You can get some that have much better rolling resistance.