I would probably avoid agomelatine. The French drug company Servier just revealed that Valdoxan is very bad for the liver.
'Very bad' is an exaggeration; only 1.4% of patients who were treated with the standard dose of 25mg/day developed elevated liver enzymes. Which is less then the risk of seizure associated with 600mg/day of Wellbutrin.
The incidence of hepatic failure is 0.06%, which drops below statistical significance if elevated liver enzymes are not detected within the first 50 days (as a median) of treatment.
As for anhedonia, having suffered from it myself for many years, I can say with almost complete certainty that no one medication will provide sustained relief from it. Just to be clear, I don't consider Medievil's 'solution' of getting high on amphetamines or abusing research chemicals as sustained relief. It just disguises the anhedonia by flooding your brain with monoamines, causing cumulative damage in the process. If you want to retain your cognitive abilities beyond 30 I recommend you persevere with the less immediate remedies.
I would avoid phenibut, it's very transitory in it's positive effects due to the rapid onset of tolerance and dependence. If you abuse it for an extended period it'll only make the anhedonia worse when you stop taking it, I know this from first hand experience.
If you're willing to risk your neurons by trialling a research chemical, then surely you'd be open to the option of polypharmacy.