I sympathize with your problem. I have tuned many bows for level bare shaft flight, so I know I have good enough form and tuning skills to do that, but occasionally I have tried to tune a bow and failed. All the ones I have succeeded on and the ones I have failed on have been high quality bows. All I can tell you is that true nock high up to maybe 10 degrees will not cause a problem with your broadheads. Just make sure your string nock is high enough (5/8” or more) so that you nock high is not being caused by rebounding off the shelf. Even on bows where I can tune to perfectly level flight, I prefer a little nock high, maybe 5 degrees, because I think it is a little more forgiving of release errors.
I have done a lot of experimenting on the bows I have failed to tune, including going from 3/16” positive tiller to 3/16” negative tiller by reversing the upper and lower limbs, which hasn’t worked. Sometimes changing bare shafts works. I have one bow where I get a 10 degree nock high with one bare shaft and a 5 degree nock high with a different one. Both bare shafts are the same model and spine of GT carbons, but bought at different times. On another bow, I was able to completely eliminate the nock high by going to a different brand of arrow, but similar spine and weight.
I have always used Ken Beck’s method of bare shaft tuning, which, as I said, has worked in most cases. However, I think there is a missing factor that I don’t understand. I hope somebody finds out what it is while I am still shooting.