Much of the stress in our lives comes from struggles related to winning or losing our battles with sin and our enemies. I believe that the line should be drawn in a different place. Winning and losing are on the same side of the line. On the other side of the line are the sidelines.
If you fight correctly, you don’t have to be stuck with either a win or a loss. You can set the contrast at win or learn, for one example. Then, the sidelines are clearly on the “other” side.
You could draw the line between “prize” and “no prize.” The prize-free side is the sideline.
Another division can be “safe” and “not safe.” It’s free to sit on the sidelines. You can get hurt or die looking for a prize in the battle.
Injuries are not the point, victory is not the point (read Hebrews 11 again), prizes aren’t even the point. Obeying the King when He sends you into the game and doing the best job of being you that you can manage is the point.
If you are going to be stressed, then, let it come from whether you are being sidelined.