Taking down A2/AD defenses with stealth:
Typically dense A2/AD defense shields are incredibly difficult target for fourth generation aircraft. The detection range of a 1 m² object for the S-400 missile batteries is typically 100 miles. That can be reduced significantly by flying at low altitudes, using the Earth’s curvature as a shield. But an F-15 flying in at 150 feet will be detected over 40 miles away which is certain death for that aircraft. And at 40 miles those HARM missiles will probably be shot down. F-18 Growlers may help, but it is incredibly difficult to jam an AESA radar.
Contrast that with stealth aircraft, most specifically the F-35, the F-22 and the B-2. The B-2 stealth technology is ancient and that bomber probably has a RCS of 0.1 m². Which is huge compared to the F-35 and the F-22. But at 55,000 feet and 50 miles away, well within munition range, no SAM battery will be able to target those planes. The F-22 has a RCS of 0.0001 m². Unfortunately because of basic physics, you cannot say that given the facts stated above the F-22 will not be detectable until it reaches a range of 0.1 miles. After all EM emissions lose power from their source at a rate of e = d^-3. In layman terms the power that needs to be dissipated increases incredibly the closer a F-22 gets to the missile battery. Basically the F-22s will be performing air superiority tasks at 30,000 feet. Far beyond radar range. They have no peer there. Then we get to the F-35 and its RCS of 0.005 m². They will not be flying at 30,000 feet. They will be approaching their targets at 80 feet and firing off HARM missiles and SDBs from 10 miles away at every single source of radar emissions.
Thus A2/AD defenses crumble.