I'm having trouble surrendering during vaped synthetic 5meO-DMT trips.

It seems to make me dry purge or burp from deep within a lot, which is very distracting and keeps me stuck in the physical state, on the threshold of breaking through.

Is this a common problem? How can I reduce or eliminate this?

I've never tried the 5. However I experienced something similar to what you described from vaping nndmt after smoking a harmala enhanced cigarette. It was recently, I decided to blast off early in the morning. For whatever reason, my body said no, emphatically.