Personally I put a layer of waterproof grease around the freehub body seal and the endcap ‘seal’ on DT wheels (not on pawls or inside ratchet mechanism, that is supposed to use a specific DT grease).
Only problems I have seen with DT 370 hubs is from water ingress, both to freehub bearings and the spring rusting and restricting pawls. Both seem resolved with sensibly applied grease.
Whole rear hub is home serviceable with a few socktets, few bits of wood, bit of grease and half an hour, plus can be converted to virtually any axle system (OEM wheels don’t usually have replacement end caps but they are available).