I find nicotine does alleviate my anhedonia to a degree; it seems to improve my sense of reward. So this reason, some years ago I started smoking e-cigarettes daily, and found this consistently made my anhedonia a bit better.
I only stopped e-cigs because after about 6 months of daily smoking, I started feeling some constant congestion in my lungs, like I could feel my lungs every day, and I thought this was not right. Of course now we know that e-cig smoke can have adverse effects on the lungs.
I've considered trying nicotine patches instead of e-cigs. Though from what I have read, nicotine in any form results in a carcinogenic effect (nicotine is not itself carcinogenic, but breaks down into tobacco-specific N-nitrosamines, which are cancer-inducing). Alternatives might be to try to stimulate the alpha7 nicotinic acetylcholine receptor that nicotine targets by some other means. Interestingly, ivermectin is a positive allosteric modulator of the alpha7 receptor, so might have some reward-increasing benefits.
I tried low-dose naltrexone, but unfortunately it seemed to slightly worsen my anhedonia, rather than improve it. And it did not seem to help my ME/CFS, so I stopped (surveys show LDN only works for about 10% of ME/CFS patients).
DMT I would not dare touch, even in microdoses, as I would be worried that it might worsen my existing mild psychosis-like symptoms. Though I've always found DMT trip reports that I read online fascinating. Interestingly enough though, there is a story online of a German ME/CFS patient who did several Ayahuasca trips. He found that while he was on the trip, his ME/CFS symptoms completely disappeared, and he was temporarily completely healthy. Though other ME/CFS patients have tried this without experiencing any benefit.
Iboga I tried a few times in micro-doses up to 200 mg. Since Iboga promotes emotions, I was hoping it might re-ignite my blunted emotions, which I have alongside anhedonia. This did seem to work the first few times I took a micro-dose, with emotions re-emerging. But then later it stopped working for me, even after taking many month's break from it.
I don't think I would have to courage to take a full Iboga dose, as the Iboga trip is very intense, and my mental health is frail.