I don't know about a study, but yes, there is a lot of contradictory information about this topic.
And this was one of the reasons why I selected STB. I never boil or simmer dmt in any form. I only oven dry dmt in its fumarate form, never over 80C.
If one goes the STB path, he doesn't have to use heat at all, when aiming freebase. Maybe just for re-x.
Generally, if the alkaloids are in the freebase form, they are prone to degradation. If in the salt form, it is better. But heat is not the only enemy, there is more. One of the worst is the oxygen. The worst is the combination of heat and oxygen.
Acceptance of the fact that our reality is not real doesn't in fact mean it is not real. It just leads to better understanding what real means.