The latter is a feather in their cap, but as the Ozark Season 3 ending showed, Navarro doesn’t tolerate even the smallest forms of failure.
If they can’t get the FBI on Navarro’s rival, there will be consequences.
Wendy and Marty got their wish of getting rid of Helen, though it stands to reason they’ve now put themselves in a worse position than before.
Navarro is happy because he believed the Byrdes have convinced the FBI to take down a rival cartel leader, and of course, because the Byrdes pulled off the casino laundering business.