A (former) redditor, u/sweaty_literature_69, AKA Spyros, cured himself of PSSD by injecting Estradiol (with Testosterone and hCG), and many others have reported large improvements following his example (including myself).
You can read the most important snippets from his Discord copy-pasted over to pssdforum.org here.
Just putting this up for consideration.
Before anyone notes that PDD is not technically PSSD, I would point out that a member of the Discord claims to have been cured of akathisia from post-antipsych syndrome by doing the E + T + hCG regimen. They might be similar enough that a treatment for one can be a treatment for the other.
In fact Spyros literally claims that Post-SSRI syndrome, Post-Accutane syndrome, and Post-Finasteride syndrome are all exactly the same thing, which he calls "Acquired Estrogen Resistance", and posits the treatment is large doses of estradiol while on TRT until symptoms abate, then PCT and quit (although he never quit TRT and intends to stay on indefinitely).