I remained functional in terms of keeping my jobs and supporting myself while I was descending ever deeper into 10 years of opiate addiction. However I wanted to die by the end of it. Eventually I just realized that I couldn't love myself or actually progress and grow in life when I was a slave to opiates, so I managed to quit for good. I still use drugs and have had some much shorter and more easily broken addiction spirals, and in general I always struggle to not use too many drugs (except for psychedelics, those don't give me any problems). I am very committed to staying in control and not using anything daily or to function or to make myself feel fulfilled, simply because I have experienced that, and I have experienced getting past that, and every single time, my life is better when I am not a substance slave. Even if I'm good at "functioning", it's still no way to live.
Playing music is a better high than any drug. Doing something you love is a better feeling than any drug, whatever it is. A lot of people forget that, and it's no wonder because addictive drugs rewire our brains over time. I choose to still use drugs, despite an addictive personality, and I sometimes think it's a bad idea, and I sometimes am glad I do. But if I had to choose between the things that actually make me feel fulfilled, and the drugs that temporarily distract me or make me feel a rush of neurotransmitters... with no hesitation I would toss out the drugs.
I'm glad I don't have to choose... but I'm also very glad that I am usually sober these days, even though I still use drugs more than the average person.