If you don't understand your own energy management and that of your opponent then you are going to get hurt. Shooting a missile off boresight does nothing for its energy. If your opponent is more careful with his energy you are looking at the silver medal position.
Detecting an F35 is not hard - lots of nations have been able to do that for decades. Tracking and hitting it is more tricky but the EM spectrum is quite large and we forced the market to look 'above and below' the typical modern threat band quite some time ago. We shall see what the adversaries come up with but the F35 delays have given them quite a head start!