How can I get RE code upgraded it’s currently RE-4? What are the chances Of it even happening ?

You basically defecated in your mess kit.

RE code upgrades are possible, for example, if you had a medical issue which subsequently got better...
Your issue, however, is and was a moral failing. There really isn't a way to objectively quantify or rescind "turd status".

You have to reach out to your branch to appeal and see if they will upgrade it. Could they do it? Sure. Will they? Highly, highly doubtful.

RE codes aren't upgraded, they identify your eligibility for reenlistment. Based on your post your separation was involuntary, and you would not he eligible for a waiver allowing reenlistment. The code serves no other purpose

SR Hunter Wallace Enter "RE-4" in the Search bar above, hit enter, and then click on "Answers". You will find several Posts that deal with this topic. I hope you have learned your lesson.

You should look at endeavors outside the military.

Did you speak to a recruiter yet?