Hey Justin, please excuse, I’ve been on holiday a few days. As far as I can see, you’re 3x9 Deore Crankset is already with a hollowtech axle. A corresponding nowerdays Road-Crankset is shimano Sora FC-R3030. But a change is only valuable if your biggest Chainring has significantly less than 50 teeth. You probably will need the Shimano TL-FC16 or comparable tool for (dis)assambly.
A bigger effort would be needed to switch to a 2x9 crankset and changing also the front deraileur.
Something you could do to get a more realistic feeling beyond that, is “bikefitting” stack and reach with an appropriate stem. (In German discussion) the last two years it has become more common to adjust the relation body-size / distance saddle-shiftlever. That is the position you spend most of the time on a roadbike. The older stack-reach relations refer to the distance between saddle and end-of-stem - that’s not helpful with a mountainbike-bar.