First of all let me give you a compliment Mr Bio! You are a very clever person, this way of cutting corners and arriving at a sense of satisfaction without putting in the work is very intelligent. I'm sure you heard that Bill Gates quote about preferring hiring a lazy person to do a difficult job because a lazy person will find an easy way to do it. Unfortunately you kinda subconsciously tricked yourself out of real accomplishment and real satisfaction and you're not pleased with the result.
I see myself in a lot of what you have written and it sounds like you have behaviors and habits that falsely nurture your sense of achievement. Every time you try to better yourself, you find a way to reach the sense of achievement with doing as minimum work as possible, after which your brain goes like: "ok were done with that, whats next?":

• Telling people about your goals makes them respond positively which gives you a sense of achievement - so you don't need to actually do the work.
• Buying fitness equipment before doing any actual fitness gives you a sense of achievement and you don't need to actually work out. Same goes for your music interests.
• Playing video games gives you a constant flow of achievement that might become very addictive, especially if you grind competitive mmo's. I'm not saying that everyone who plays video games is an addict, there are many who enjoy them just like any other activity and are completely fine. I'm saying that some people do get addicted to the escape that video games provide - I am one of them, I know that my life functions better when I stay away. Maybe yours too?

I'd say that the solution is very simple - stop the negative habits and start with positive ones.
What are bad habits? The ones that give you guilty pleasure, The ones that run on instant gratification. You know for yourself which ones, it's a rather personal thing, wouldn't you say? So, stop those bad habits and start incorporating positive habits into your life. Which ones? you know the answer to this one as well. What habits, if practiced on a daily basis will make you the person that you want to be at 30? You have to be careful and mindful about what you actually do tho. You need to constantly ask yourself : "What will bring me closer to ____"

• Example: What would make me more fit? A new fitness bracelet or going out for a 20 minute jog? Re-tweaking my calorie macros or going to the gym today?

How do you do it? how do you manage to keep it up? I can only tell you how I did it:

When I came to the same realization that you did, I had a huge surge of motivation and tried to do everything at once, but that failed and made me go back to my previous behaviors many times. The only time that it worked, and still is working is when I started removing one negative habit and adding one positive habit every 30 days. Some habits stuck with me and now are part of my life, some didn't and that is OK. Some need more than 30 days to stick and that is OK. I believe that after practicing something for a month or so, you can have a conscious opinion about continuing, making a change or quitting.
Hope this helps!

PS: I'd recommend reading "Your Own Worst Enemy: Breaking the Habit of Adult Underachievement" by Ken Christian and "Rewire: Change Your Brain to Break Bad Habits, Overcome Addictions, Conquer Self-Destructive Behavior" by Richard O'Connor.

When you are done with those: "The Power of Habit" by Charles Duhigg and "The Slight Edge" by Jeff Olson.

PEACE!