If they really want to play a good long game. Have it be Jungle Boy. They nonstop talk about his declaration to be a singles champ in 2023, he just buried his feud with Christian which helped elevate him, and he's already got a good amount of fans behind him. MJF can just play his usual smarmy heel and cast doubt on anyone beating him, namely Jungle Boy, but begin cranking up the desperation when Jungle Boy's momentum starts going full tilt and it can't be denied. Cole is a good side feud in the mean time, but Cole works much better as a heel than face IMO.