10mm through axle hub use in traditional frame?
If understand right, you've got a thru-bolt style hub and it's not fitting correctly in the dropouts. You're proposing to take a standard 10mm axle instead, use that in place of the thru-bolt, and put a QR through the whole thing to secure it.

(Thru-bolt is the more commonly used term for the type of hub that fits in a standard QR-compatible dropout but uses a continuous-diameter axle for extra stiffness.)

I think it would probably be fine to do what you propose. Hypothetically one issue could be what if there were other aspects to the hub's design that were relying on the stiffness of the thru-bolt to maintain bearing alignment, etc. But that's very hypothetical.

However, if a 10mm threaded axle fits and your 10mm thru-bolt doesn't, you're probably talking about taking off a very minuscule amount of material from the frame to make it work. In most cases I wouldn't feel any compunction about just doing that, especially if this is your bike and this is the hub you want to use with it indefinitely. Back in the days when more bike boom era bikes showed up in shops for repair, I filed a number of 5/16" frames and forks to take replacement wheels with 3/8" or 10mm axles. That's about 30 times the material you're talking about taking off and maintaining symmetry was never a huge problem. Just be careful, do the same number of file strokes on each side with your best attempt at the same amount of force, and go slow. Make some sweeping motions with a round file to do the enlarging of the rounded part, if you even need to in this case.