I confess to not having much experience with harps, but I do have lots of experience with other kinds of instruments, most of them stringed. A warped neck sounds pretty structural to me, something to be looked at very seriously. If the warping is more than minimal, I’d be very hesitant to buy into problems. If you have a luthier who could look at it you might get a more expert opinion. But if not I’d proceed with extreme caution.
If you like the sound of Troubadour I, you might