communication tactics
This is standard "Pro wrestling" tactic : both contestants needed to create the illusion of a close alliance to further their agendas. Now that is growing old and hampering their individual progress they must appear at odds, Musk to further his agenda in non-US-friendly countries (Starlink and Tesla come to mind) and Trump to reinforce his US-based support which is dwindling. Hence the very public bitch-slap match akin to a former "temmate" smashing a chair on his former ally in the middle of a wrestling ring. I believe it is called a "beef" in the Land of the Great Again, and it benefits both parties.
It also serves to mask the fact that they both worked together to pass measures that will durably harm their respective supporters : the Bidden did it all" excuse was wearing thin, they both needed a diversion.