Aggression

Yeah, I should probably give up chess for real. 
I have tried but I keep coming back... I hate myself for not enjoying a single hobby throughly

Insecurity.

What is the cause of it?

?

failing high school (12th grade), getting degrees from the worst unis possible, getting a plastics diploma from a bang average institute, not being able to do a PhD nor get a scientist post, failing physics entrance exams under the sun, poor study, poor focus, poor discipline, poor consistency, extreme distractions, extreme procrastination and I also suck at music too. I am glad that I got a job but it's quite limiting so my future is still up in the air. It hasn't helped me become better. 
Chess is also an addiction to me. I hate it but I keep playing it. I don't know why nor how. 
Chess has become less and less enjoyable over time. Any win is just meh and a loss is just frustration.

Nothing gives me joy nowadays

we are all human beings - fallible and inerringly susceptible to vice

we fall into bad cycles of life (those that do not provide fulfilment) because they are easy. the challenge is to break those cycles and replace them with good ones (which do provide fulfilment).

this is much harder, but it is the only way forward (in my opinion)

I thought having a job would break that cycle but it doesn't.

Apologizing and admitting a mistake helps a person grow. We have the right to make mistakes and apologize. It's a right.This is a.efffecrive method to evitate arrogance and be better.Good for you

My wife's a psychotherapist but she retired a year ago. I did learn some stuff from her though. I would guess the chess is to replace something that's missing. I'm really guessing here but maybe your parents led you to believe that your life would be a success and that failure is something that isn't acceptable. So success in winning games isn't a joy because you're just fulfilling expectations. You know what? How can you learn to love yourself and accept yourself? Accept your failures and in future always try to learn from them. Don't just move on through life in a sort of never-ending succession of meaninglessness. Learn to love the present moment .... now! You can actually make a decision to do that and it can change the way you approach life if you really mean it.

Always be honest with yourself but see the good things too.

I hope that helps.

I don't know how to do love myself and learn from my mistakes effectively. if I did, I wouldn't be here and still be in this situation...

But I am struggling to get over them and learn from them. I still make the same mistakes

But recognizing it is a very important first step ! A incorrigible person won't recognize it, but you will. The next step is truly wanting to change. Not just with words, but with your deepest psyche.The Real Inner You Consciously Awake

Don't forget to breathe out!

I know that. That's the point I'm trying to make. You can't all of a sudden read a few posts here and they have the answer, because it's entirely down to you being willing to get rid of the burden which you don't know exists but which is preventing you from being happy. There's no quick abracadabra.

First you have to really want to move on. Then you must take the right steps. Your thread here is good as a starting point and you've asked the right questions and others have tried to help you. But one of the problems holding you back is that you are depending on other people to help you maybe like the way you depended on your parents when you were very young.

You have to move on to depending on yourself and to do that you might need professional help. Not CBT or anything stupid like that but real, person-centred counselling. I can't advise you who to go to and many of them are new and not much good. Avoid anyone who claims to have many "psychotherapeutic tools in their toolbag" or "counselling tools". Avoid anyone who sells their skills partly by looking attractive or sounding too attractive. Avoid them like the plague. They are all people who are not grounded themselves (in honesty) and so cannot help you to be grounded. Try to move away from relying on the help of many people as in this thread. All that is happening is that many well-meaning people will confuse the matter even more.

Ultimately, yeah. I have to figure it out which is frustrating to me because I have been doing that for many, many years and keep coming short.

I have no idea how on how to fix this issue effectively. 
To me, there is no such thing. I am completely loss. 
I am far too moody and inconsistent.

Firstly don't worry about anything. The chess thing is a derivative of a few small mental insecurities, that's all. Since you're probably playing chess to escape the turmoil of emotions, I would recommend giving chess up entirely for a year or two and finding some other way to use your energy which is more physical. Chess isn't a sport and so it doesn't necessarily do you good. Remember that!

Ummm... I can't barely play sports nor do any exercise... 
I am extremely physically weak...