They don’t call the F-22 and F-35 fifth generation fighters for no reason. There have been many iterative improvements since the ME-262 and Gloster Meteor that would not have happened without the intermediate steps.

yes, jets are composed of thousands of components, each attached to each other in assemblies. The assemblies are then integrated in such a way as to perform the functions of a jet: providing thrust, providing lift, steering, holding fuel, etc.

Most of these systems are evolutions from previous designs, however. How much is completely new?