Valid point but I would argue decapitating a cartel never leads to the cartels dissolution. Somebody moves into the top spot and she knows that. Unfortunately what I've seen (no expert of course, but I find the topic interesting so I've learned some), but what I've seen is old-timers tend to favor trying to be low-key while young bucks enjoy dominating through violence. My own city has has gangs (midwest) and we started having "hybrid gangs," no centralized leadership and much younger average member, violence shot up. There weren't any mid-twenties and older shot callers telling the young bloods that violence draws attention which constricts business. I think Mya has been around long enough to know that her actions would not have the desired effect. I believe she acted impulsively and partially out of a desire to give her superiors the middle finger.

This next is even more hypothetical, but with an FBI deal in place, Navarro would have even more incentive to calm his cartel: become too bloody and the FBI might decide the relationship is far too risky to allow to be public and they might fabricate pretext to kill him.

In real life I'm pretty sure the Cartel de Sinaloa has some sort of agreement with the government, favored status of some kind, because they are marginally less violent. They arent known for picking on the civilian population whereas others do not give one F about killing/kidnapping/etc., and I would bet this restraint is largely due to the boss El Mayo who is in his 70s and has never been arrested. There is video of the current president of Mexico walking up to a white truck and greeting El Chapo's Mom (former co-head of Sinaloa).

I think currently there is no simple answer to the cartel problem and the best that Mexico can really hope for is peace and the dominance of the most restrained cartel. Again, I'm no expert but just my thoughts.

I know this is more than you were looking for but I'm going #2 and find the topic of interest. Be well friend.