"4th generation aircraft are not sustainable in modern combat without a wide array of assistance from EW etc. "

But isn't that true of the F35 as well?

On it's own, I doubt it would survive much longer on the eastern front in Ukraine.

In Iran the F-35 also did not fly around freely while the ground radars were active. They had to be taken out first. For that stealth was probably useful (and in general it is).

But it is not making them invisible - and cheap sensors and AI is likely to counter it soon. Because sensors and analysis will get better over time and sensors also better and cheaper. But the stealth will remain largely the same. It cannot really be upgraded for existing jets.