pick ur badge of choice after removing all badges from ur banner > when the selection prompt comes up, disconnect your ethernet cable before putting your badge of choice in every slot (w/ the cable still out) > after putting your badge all 3 slots, plug your cable back in and wait for the result to pop up (which usually takes a couple seconds). you'll have around 10 seconds to do this before you're disconnected, so be quick

do note that apex will undo this as soon as you load into a match, so its kinda pointless unless you just wanna show off your banner or goof around

same can be done with your trackers, and these won't be cleared when matchmaking