@FruitSnack24
As someone who is also a tall and slightly skinny guy(6'3
≈185lbs), I had a lot of trouble putting on weight for athletics early on(6' and 140lbs around 20 months ago). I had a swim coach in my eighth-grade year who in response to me telling him that I wanted to be stronger, showed me a workout plan to build my strength through calisthenics. It follows a pretty basic principle. If you improve slightly every day, in the long run, you will see large gains. He told me to go out and get/print a paper calendar and write my max amount of pushups and situps (without stopping) in the box that was today. Each day, I was to add one pushup and one situp. I did this every single morning before school for three months and it became part of my routine. I went from being able to do around 30 pushups and 60 situps to 100 situps and 130 situps without an excessive amount of effort. Eventually, it started to take too long and I got bored so I purchased some weights and a gym membership and started to lift in my basement and at one of the gyms in my city instead. Since then, despite getting bigger and stronger (with the help of age and maturity), I am almost certainly unable to be able to the same amount of reps as I once could, but maybe after writing this out I'll start again.
This same idea could probably be applied to your other events as well. If you run the shuttle run or mile or do pullups (I suggest one of those bars you can wedge in your door frame) every day...you will get better. If you work it into your routine you will not only get stronger but you will feel better as well. This program opened a door for me that, now as a student in mid-highschool, has lead to a pretty consistent gym routine and discoveries about how to better my mental health. (there's no problem too difficult after 100 angry pushups on your bedroom floor)
This is just one way and something that I felt that I could share not just with you but for anyone looking to get stronger or start a workout routine.
Reps and routine are the answer brother. Good luck.