Pure speculation as always…
Fringe pre covid into early covid KJ was the next upcoming big thing. Young, athletic, and hungry to be out competing. Great personality, got a bit of dg rich money, got comfortable, and lost the drive.
100% not saying he got lazy and started dialing it in. More like it's fun when you're in your early 20's, sleeping on couches and partying every night you're on tour. Eventually you outgrow that phase…unless you're Nikko.
Competition kept getting better and he's now irrelevant, damn shame because the dude was very likable and had a unique game. He was good on lead card coverage because his play wasn't identical to everybody else.
My guess is prodigy tried using whatever leverage they had to get out of a deal they weren't breaking even on, and KJ was ok with the mutual split. Hopefully a change of scenery breathes a second wind into him, he's definitely young enough to still play at a high level for a while.
Pro dg is a better product if KJ is in the mix.