It makes more sense than using a stealth aircraft as a stand-off jamming asset.
(1) Jammers aren't always on, it's legal to sneak up or turn them off when threatened;
(2) Jamming making you emit isn't equal to giving radar return. Yes, they know where you are; it's still not a
normal firing solution.
(3) F-35(and all it's contemporaries) is meant to jam with it's main array anyway(which is super powerful). Su-57 in particular jams in all directions from Ku to L. Like, why not, if you can choose when;
(4) Stealth isn't some sort of legal obligation -
at worst, you're going to be as unstealthy as f-15 always was. F-35 is cheaper anyway.
Advantages here are that:
(1)f-15ex is a twin-seater with the most modern back seat in the world;
(2)it simply has more fuel;
(3) distribution of power generally favours twin engine solutions over powerful single engine ones (though huge difference in airframe age can nullify it;
(4)For stand-in jamming, f-15ex with pods is a better match to both 4th gen and clean f-35 formations. Podded f-35 only truly matches superbugs probably... which already have a better e-escort.