I have a hard time believing one can be motivated with full blown anhedonia. Motivation requires pleasure. I had the same mindset as you, and still do to be honest, except when I have "motivating thoughts" no energy, no dopamine comes out and it's like I'm always swimming against the current. I still do stuff because I have to and (also?) believe there's no meaning in life if you are average, but can't say I am motivated since I can't get my brain to care emotionally about anything. Socially, I can act completely normal without much effort expect with people that are not my age or don't share similar interests. So right now, almost everything I do aims in trying to get out of anhedonia. Once I make it. then I can continue with my life, and feel the beauty and meaning of this world once again. It won't be easy and most likely going to take a while. Good luck with quitting your addiction, do not fail.
I have probably about 80-90% anhedonia. I do laugh a few times a year, but it is very rare. I haven't been able to cry for years, even though i try my hardest. I feel like if i am able to cry, it would be a great release for me.
I never felt rewarded after completing and achieving very good results in both my degrees.
Socially I can 'act' normal as well, but it feels very fake, and I hate the fact that it is not natural.
If it helps, I've read about multiple people who acquired anhedonia via stress, and after 2-3 years, it went into remission. I'm yet to hear about anybody who smoked through teenage years while the brain was developing, and recovering.
Anyways, I won't fail, even if it takes me 4-5 years to feel normal. If i'm still like this after that long, I will try out ibogaine, or other similar substances that may aid me in the long-term.
This is truly no way to live, and I would have killed myself a long time ago, except for I can't because it would destroy my mother who has tried her best to give me a good life. I wish you well in your journey to remission my friend.
Cannabinoids have been known to trigger symptoms of Schizophrenic Spectrum Disorder - psychosis is often the one everyone talks about, but I don't think it's unreasonable to believe that it can trigger negative symptoms and flat affect as well...
Have you ever considered that perhaps you have some variation on Schizoidal "Personality Disorder", or Schizotypal "Personality Disorder" (they're not PD's, and the whole label is a complete misnomer - hopefully the labels will change in the future) - they are both a form of mild schizophrenia, and some of them, as well as what's called "Schizophrenia Simplex" are considered to merely be different positions on the schizophrenic spectrum - a bit like how Autism is also a complex, non-uniform, highly varying disease.
Flat affect, anhedonia, difficulty deriving pleasure from socialising... these are actually aspects of Schizophrenia to an extent as well.
The fact that the symptom were triggered after Cannabis-abuse made me draw the connection here... have you considered anything like that as well?
In theory, something like Ondansetron, might then be useful. (a 5ht3-antagonist)