First, I’m sorry. My Lemmy client shows you have 5 replies, but I can’t see what they say. I may be repeating others’ comments.
You may not be able to. Competitive people are competitive. Unless you are willing to concede their superiority in all things, or to refuse to compete, they will compete. It’s just some people’s nature.
Most people I’ve met are competitive only in areas: where they’re capable of competing. My brother-in-law is the most competitive person I know, but he’d never accept a programming challenge from me and would surrender, because he simply has zero knowledge in the space. But he’d race me downhill skiing, even though he knows I’m a better (or, maybe, just less conservative) skiier. So I avoid competing with him most of the time by refusing to participate. I just say “no, not interested.”
It might work for you. If they’re the types that treat that as weakness and start using you as a punching bag, then I suggest you’re better off finding new friends, 'cause those kinds of people are just worthless assholes. But if they’re just run-of-the-mill competitive, because life’s funner for them when everything is a game, then just saying you don’t want to play might be OK.