Applications of Abstract Algebra

So I'm studying abstract algebra rn, just for fun and for me to have a taste of college mathematics, and I'm wondering... what are the applications of this in other fields of mathematics? Cuz I'm also training for the local hs math competitions in my country and im wondering if I'd actually reap any actual benefit from studying abstract algebra in olympiad style problems, or if I'm just doing this for fun. I'm also studying linear algebra and calculus at the same time, partially for fun too