Hyperbole.
Maybe the F-35 could be used in such a role in Kaliningrad. Which is a tiny Russian exclave surrounded by NATO airspace.
In Ukraine the NATO airspace is just too far away from the front, where the air defense systems are concentrated, for the F-35 to play any meaningful role. You need larger aircraft with more powerful sensors operating at higher altitudes in a persistent fashion and even then there will be limits. This task is likely being done with large ELINT aircraft or satellites.