Ronda looks relatively bigger and certainly more athletic than most women. Logan Paul looks relatively bigger and certainly more athletic than most men. Colby does not. He just looks like a fit, regular guy.
He does not have the type of athleticism conducive to pro wrestling - relentless cardio isn't going to get you over.
And, despite popular belief amongst the mong demographic, Colby is not particularly good on the mic. That's not some ace up his sleeve in pro wrestling terms. He is no Chael.
At 37 this is not a serious career path. TKO might bring him in for a single bullshit angle, but he is not going to make a big run at it.