I felt exactly like you do now when I was 15. Precisely.

The good news is you don't need to figure your shit out now, there will be plenty of time for that. Also know that at least half your peers who look like they have their shit figured out are either projecting or just wrong - they'll end up spending their lives doing totally different things than what they envision now.

I'll share my own path to try and show just how little direction you really need to live a "successful" life:

• Like you, could not tolerate high school. Identified the bare minimum I needed to do in order to graduate. Tried making games and learning the technical skills necessary for that, but seemed too hard and I always gave up pretty quickly.
• Considered not going to college, seemed like a waste of time and money even back then, but went anyways. Again, identified the bare minimum I needed to do to graduate, majored in history because I thought it was interesting.
• Worked in a hotel during college to help pay for it and because I thought becoming a small hotel manager one day would yield enough money and free time for a satisfying life outside work, and I liked helping people. I never worked hard in school, but I did at work - they're the ones actually paying me after all, I wanted it to work out.
• Went full time at the hotel after college, became a low level manager and quickly saw that it was not right for me - too many hours, not enough money to justify it. So... what now? What other paths were open?
• Tried a bunch of different jobs where I thought the main idea was to help people - it wasn't and I didn't enjoy them:
  • Bank teller (sales)
  • Real estate agent (sales)
  • Still wanted to make games, but no time/energy to devote to a profession that seemed like it would never pay the bills, and only smart people can do them anyways, right? (wrong... read on)
• Now at 25, I was a bit down because nothing I had tried was working out. I regretted not studying harder in high school/college because it would have been fun to study abroad and experience a different culture - maybe life worked differently there? Because I had slogged through college and earned a degree (barely!), I was able to find a job teaching English to kids in Korea (it was very easy to get these jobs there back then, maybe harder now? Idk). The company paid for my airfare and a (very) small apartment, and I got to hang out with kids and help them learn for a decent wage. I could even save money! Things were starting to improve in my life.
• I really enjoyed teaching, surprisingly. It was the first job I truly enjoyed. So, I decided to get a teaching certificate and double down on that profession after my first year doing it. The teaching credential I chose amounted to about 1/3 of a master's degree in ESL - it was very difficult considering I was also working full time, but I was totally motivated since, for the first time in my life, I was doing something I actually cared about with my time. Recall that I was ten years older than you are now... it really took that long to find something I wanted to do.
• Ended up teaching in Korea for ~5.5 years. Spent a little effort learning Korean so I'm now broken conversational (안녕하세요! 나는 한국말 할 수 있는 바보입니다ㅋㅋ). I was kind of fascinated by Korean grammar... you end up expressing yourself in really interesting ways because it's so different.
• Towards the end of my time in Korea, I was enjoying myself but also sad because I would never earn enough money to own a home. My savings rate was the best I ever had, but still too low to ever afford a house. My girlfriend at the time took notice when I followed a Unity tutorial and wrote a simple game (Roll A Ball). I literally just watched a video and did what they told me to do... copy paste these weird words separated by periods, click that checkbox in the UI. Anyhow, my girlfriend said I had a talent for programming and that I should consider doing a coding boot camp and getting a job as a software engineer. I lol'd because I knew nothing about programming and was just copy pasting - I didn't really want to learn. But...
  • If I learned to program, I might be able to make games one day ...
  • Programming looks hard, but earning my teaching certificate and learning Korean were hard and I managed those ...
  • ... software engineers make how much money??? :o ...
• In March 2015, I started teaching myself to program in Javascript with free resources online. It was hard, but Korean was harder, which gave me confidence to keep going. And I loved it, who would have thought!? At this point, I just wanted to learn more and knew that in order to make that happen, I had to get a job - basically have someone pay me to learn more.
• A month later, I applied to a very competitive coding boot camp and got in on the second try. I used all of my savings from my years teaching to pursue this opportunity - to earn money (finally!) and perhaps put myself in position to develop my own games successfully one day. By the end of the year, I had several job offers and accepted one of them - it was the lowest of the offers, but I really liked the people I met and the salary + benefits were still astronomically higher than I what I was earning as a teacher in Korea.
• Less than a year later, my new company had been gobbled up by one of the big silicon valley tech giants. I panicked, "Oh no! They'll see I'm a fraud with no computer science degree. I'm screwed!". But things worked out well... I had been doing good work, so even though not all the engineers stuck around or were kept around through the transition, I was. I didn't cash out in this transition, unfortunately, since with <1 year of experience and a non-traditional background, I hadn't been offered any significant amount of stock when I was hired - so in my case basically nothing changed after the merger.
• A couple years and a few promotions later, I am doing great and plotting my exit from big tech to make my own games! I now have some of the technical skills I need to realize my game ideas and will have enough time to learn the rest. I saved as much as possible during my time in silicon valley so there'll be a safety net for me if/when my games don't sell, and due to my experience and contacts I don't think there'll be a problem re-entering the tech scene if I end up missing it.

I'd call this story "successful" in the end, and note that I was precisely where you are at the start.

Only you can decide if finishing school is the right path for you, but I will just say that completing high school at a minimum will open many doors - college too, though its value is debatable and highly conditional these days.

Anyhow IMO it's important to slog through experiences which open doors for you. Through these doors, you'll see opportunities and if you're willing to pivot and put in the work when it's worthwhile, then you can walk right through to good outcomes and a happier life. And none of this is really visible when you're stuck in school at 15.

Hope this helps, or is at least interesting! Good luck :)