After further testing, adding 4% NaOH drops elutes a lot a more stuff than the weaker baking and washing sodas. Typically when doing this, pH shoots up to 11 or so, then comes down within minutes and liquid becomes more fluorescent. I repeated this process until the pH stabilized at 9.4 after dropping (about 5 NaOH additions).

However, the resulting liquid is not active after neutralizing with vitamin C and doing a bioassay. Maybe the pH spikes could be hurting the psilocin, or the psilocin has not yet been eluted (I'm assuming Psilocin was originally bound to the resin since the original tea treated with resin is not active).

Reading more about this, the lab folks use buffered solutions with increasing ionic strength to help elute drugs. Sometimes they add proteins that help elute other proteins.

So to elute psilocin in mild conditions these additives may do the trick. Stuff like ammonium acetate (which can be sublimated off) and/or an arginine (a basic amino acid that should have a positive charge and may compete with psilocin binding to the resin).

Etid: Attaching some info on how to select pH and buffers. Also attaching a publication from 2016 discussing how arginine helps with elution. Also, in this thread someone claimed arginine can be precipitated by glutamine, with is surprising but can be tested.