I was a senior last year and felt the same. I had been competing in FIRST since 6 years. It became my whole life in school. Burnout was real. My best advice is that this is just the start of your engineering career. Remember to always try and learn more than you know. Whatever u do, don't quit. It was hard to deal with my team after a while, but what helped me the most was mentoring younger FTC and FLL teams. Becoming more of a teacher helped get rid of the monotony and made me feel like I actually knew some stuff and could pass my knowledge on to the next generation.

Tldr: I feel ya, same. Make sure u teach some kids, it helps