But you wouldn't start creating a bigger RCS in the sky until it's absolutely necessary to throw a decoy.
For the TRD to be deployed, you are either in a situation where your main goal is to jam the radar, for example, in case some helicopters or older jets need jamming support, or your stealth has been compromised to an extent where your only way of survival is through jamming, hence present the decoy as a more viable target to the radar. In either case there's no need for onboard EA, save for the radar. Otherwise the F-35 will exclusively use its stealth, with minimal to no emissions.
Israel’s Specially-Built F-35I Test Jet Just Touched Down In-Country
This one-off version of the F-35I stealth fighter will help introduce new weapons and avionics for the “Adir.”www.thedrive.com
In case the IAF actually decides to chase after the F-35 in earnest, I'm betting it's going to be for the Israeli version. So it's not a surprise it was the Israelis who showed off the F-35 to the IAF Chief.