I've been on depression and mental health subreddits for a long time and I see a lot of the top rated comments or stories that seem very different from my experience

For example in countless places I see the advice of exercise, people say that exercise will treat depression but depressed people are tired to do so and other people say exercising at least 30 min a day will make you a lot better and there are some stories that overcame depression by exercise alone

I do weight lift 6 times a week and do 30 min of cardio 3 times a week yet I don't feel any difference at all.

Or a lot of other people saying that finding a purpose or fun hobby helped them a lot even one guy said he cured his depression by learning guitar. This seems very illogical to me isn't the inability to enjoy hobbies (anhedonia) a symptom of depression? If these people could enjoy things doesnt that mean they werent depressed to being with? Im confused.

And there are countless people view depression as just overreactivity to negative life events and many depressed people said that pills helped them be realistic in their emotional reaction. I don't understand exactly whats depression but most people seem to view it as persistent sadness and negative thinking and so it's just a temporary feeling that comes and go.

But that's really different from my experience my depression isn't negative thinking or anxiety but rather I became lifeless joyless no interest in doing anything and my pleasure is impaired I can't enjoy foods or music anymore I can't feel love for my partner I can't enjoy shows or video games and I'm so numb I can't even be angry anymore.

Thats how my mental illness feels and I thought its depression but as time passes im beginning to think its something else

Like many people tell me to work on the "root cause" or seeing a therapist or changing my environment/work but I don't know how that's related to my condition I don't why I have these symptoms or what caused them I don't have a reason to be depressed or "root cause" that started the problem. So they make me doubt if I even have depression because If I actually have depression then why don't these advice help me?

And scientifically speaking many papers claim that depression is highly treatable and antidepressants/therapy have high success rate yet for these 2 years I've probably been on every drug and supplement on the planet yet nothing has helped me at all if depression is highly treatable why nothing works for me? Am I one of the worst cases in history?