I put the NGK Ruthenium plugs like in #4 in the wifes Kia last year because they were slightly less expensive than the Iridium plugs. I can't tell much difference in her car, I think it idled a bit better, but that is comparing the newly installed plugs to ones with 60,000 miles on them?
From what I could find out from some google searches, the Ruthenium plugs don't last as long as the Iridium plugs, but are supposed to have "high ignitability"?
The claim is they are supposed to get better fuel mileage?
Some info from google search:
https://carphrases.com/ruthenium-vs-iridium-spark-plugs/
https://vehiclefreak.com/ruthenium-vs-iridium-whats-the-difference/