I have certainly not felt that defensively the problem was with the guards especially on on-ball-screens - it has been with the forwards/centers getting caught in no man's land and not guarding either player - not forcing the guard to move around them by not showing strong enough, and at the same time allowing the pick player to move into space. And the resulting parting of the seas defense speaks to the rotational defense of the other three players as well.
I have actually been really impressed with Dupree - she is shooting 5-10, with 7 rebounds, 5 assists, 1 steal, 1 block, and zero turnovers in 35 total minutes. She has also influenced many more rebounds by keeping them alive for another teammate to grab. Her defense has been solid without fouling.
USA fouling has not been too out of balance with their opponents, but they have clustered them into single quarters so in both games the opponent has had at least one quarter where they have lived at the line. And they have been making stupid fouls - Griner picked up one offensive plowing foul and a defensive foul on a layup she wasn't contesting but she just ran into the player after the shot was taken - DT with her elbow and a few others, Angel with her fouls.
I also found it really interesting to read Geno's comments about the new format and how it was bad news for the USA - with only 3 games instead of 6 prior to the knock-out stage the team has fewer games to actually train. With the rest days the depth of the USA squad is less effective as well since the other team's starters will not be as worn down by the medal round.
The women's hoops world is changing faster than the men's - with all of the viable international leagues, there is actually a lot more professional work for international players than for USA players, and the fact that the USA players play in those leagues raises the quality of the competition. We are rapidly approaching a time when the three months of training for those teams will be a deciding factor. Realistically, at this moment for this USA team, the full roster of either the Mercury or the Lynx would be playing better than the USA team because they have had those three months to gel as a unit. The hope is by game 6 of the tournament that will not be the case.