There’s absolutely nothing wrong with looking at the overall team speed as a problem.
However speed is just one factor to consider here. When defending for example, body positioning and where the defenders eyes are focussed would be a higher priority in my opinion.
In the AFC Championship game Stephon Gilmore made perhaps the play of the game when he reached out and swatted the ball away.
Point is that speed often has very little to do with the majority of plays on the field.