Avengers: Endgame Super Bowl Trailer Breakdown - 13 Things You Need To See
7. Target Practice
Everyone has their own way of dealing with what happened. Steve Rogers goes to a support group to talk about his feelings. Natasha Romanoff, trained in the Red Room, uses a shooting range at Avengers HQ to take out her anger and grief on some practice targets.
This makes sense for her character, because it's something she can have a level of control over while everything else goes to s**t, suggesting she's struggling just as much as everyone else to cope.
What's also worth noting though is her hair, which apart from the different style is also visibly longer than it was in Infinity War, further confirming at least a slight passage of time. This is the same style she has when she finds Clint in Japan, meaning that must come after the time jump.