Playing sports with your boss outside of work is honestly cringe

I mean, you can't kick their ass, not unless you want to make it a problem for yourself on Monday. If your boss is a gloater or a sore loser, you'll be hearing about it for the rest of your time working with them.

If you pick the sport and win, then it'll seem unfair, if you pick and they win, you'll look incompetent. If they pick and win, it'll seem unfair with a side of power tripping, and if they pick and lose, you better hope they are mature enough to deal with it. The whole thing is just dumb

And the worst thing, if you have a boss that suggests "having a game of XYZ after work", you already know they have some weird glory moment running in their heads, it's already crossed from a working relationship to some buddy/buddy competitive thing, probably to feed some ego need.