Any Predators hunting on Earth are playing the game on Easy, which means it’s extra embarrassing when they lose.
The Predator franchise is based on a single, beautifully intriguing idea: highly advanced aliens periodically visit the Earth in order to hunt the deadliest things they can find and collect their skulls as trophies. Over the course of five movies (not counting the crossover films that pit them against the Alien franchise’s Xenomorphs, the results of which cause us to lose regardless of who wins), it has become apparent that our planet has been a hunting ground for Predators for centuries. However, one can argue very easily, that Earth is the most embarrassing place for Predators to hunt and likely something of a training wheels planet.
By any reasonable measure, the technology of the Predators (sometimes known as the Yautja) is far beyond our own; the alien species self-evidently have mastered faster-than-light interstellar travel, targeted plasma weapons, personal cloaking devices, and many others. It is a small mercy that the culture of the Predators seems to revolve around individual hunting forays and single combat, because otherwise, they could wipe all life off the planet pretty easily.
However, that implies that any Predators who are defeated by the primitive types who live on this backwater planet using its laughable technology must not actually be all that good at hunting. Think about it: if a human hunter would go on safari, armed to the teeth and invisible to the naked eye and also was armed with heavy explosives, just in case, then still somehow got straight-up murdered by a lion, we would assume that hunter was pretty boneheaded.
As such, we have to assume that the Predators dispatched by Arnold Schwarzenegger, Danny Glover, Adrien Brody, Boyd Holbrook, and Amber Midthunder (and all the ones that got killed in previous hunting parties) were either incredibly inexperienced, incompetent, or both. In last year’s critically acclaimed Prey, the former was actually part of the conceit, with the Predator facing off against a young Comanche woman in the 18th century being described as a younger, greener hunter than we’ve seen in the past.
That must explain in part by Amber Midthunder’s Naru is able to dispatch her far more formidable foe; with no disrespect to her character, any Predators who allow themselves to get taken out by a human is just not good at what they’re doing. While we know very little of other planets on which Predators go hunting, we definitely know that there are far more deadly species in the universe than humans, thanks to a glimpse of a Xenomorph trophy skull in Predator 2. If Predators can singlehandedly dispatch acid-blooded armored H.R. Giger nightmares from space, they should be able to handle soft simians like us with little issue.
It seems likely that the Predators that we have seen throughout the films are something of underachievers in a species whose main drive is to be the deadliest hunters in the known universe. You don’t send inexperienced workers to do the hardest missions; you give them a Nerf scenario where they can learn from the easy stuff. For Predators, it seems likely that going to Earth to bag a trophy is the equivalent of going bumper bowling. It has to be incredibly embarrassing to manage to still somehow get a gutter ball.