Yep, new rim. Truing won't fix the dent. Some dents can be straightened out but, alloy is soft, and only likes to be bent one way, once. I took a big dent out of a Mavic Kysrium last year. The alloy was scary soft but it was pefect afterwards. As strong as before? Not sure....I sold the bike
So if you can't fix the dent = new rim, maybe new spokes too because the length required for a different rim is longer/shorter. You might find yourself at 2/3 of the price of a complete Stans or Hope Pro on Stans Arch/Flow (what you should be using).
Keep in mind that a pair of the XT hubs are at most €75 on ebay, and unless serviced every few months, the bearings and cup/cones turn to s**te. So I wouldn't spend too much just trying to save them. They are nice and work well otherwise.
I've heard that Scott can build a good wheel??