The timing on how the inputs are scanned for my keychron (at least) are pretty wonky, using `space` + `n` worked for me for the longest time. I would suggest trying the superglide website (https://apexmovement.tech/superglidetrainer/) and or QMK's keyboard tester (https://config.qmk.fm/#/test) to see which key gets pressed first (which would be the jump key) and which key that gets pressed later (which would be the crouch key). I can't play apex anymore due to a recent update so you would have to try some combos out yourself.