Civ 6 isn't designed to be a competitive game. Balance, UI, time-scaling, optimization...take your pick. Even something as basic as the barb mechanics makes the notion of a competitive environment somewhat a joke (one person gets barb horsemen inside 10 turns off a scout impossible to see in advance, other one gets almost nothing).
The outcome of a competition would be so noisy you'd need tons of games, each taking unnecessary hours, just to get a picture of who's actually playing better, on average.