Ethanol isn’t all that easy to remove, so telling you can just go straight to decarb without actually doing it myself and getting or doing the residual solvent analysis would be irresponsible.
I have done that work for decarbing BHO, and in that use case I would characterize a pre-decarb purge as “completely irrelevant”.
“Mostly irrelevant” ?!?
Depends on how you actually implement your decarb and what you’re playing with for rules.
Eg: if you Decarb under pressure to retain terps? (or “jartek” in a well sealed jar), then you will also retain any residual ethanol.
Are you able to submit samples for 3rd party testing? Because a data informed purge is always better than just guessing.