In other words, more than enough reason to be paying attention to the new Challenger Series!
Tacked on at the bottom of the achievement page (and all the more missable for it), Challenger - Series II offers 10 new achievements to test your mettle against, largely focused around various feats that can be accomplished by taking down the various Elite Bosses that inhabit Teyvat.
Most of these challenges aren’t incredibly difficult in and of themselves, but one or two need a little thoughtfulness to pull off. The “Dip, Duck, Dive, Dodge, Defat” achievement (avoiding Oceanid Hydro Mimic death explosions) for example may need a shift in playstyle… and a fast sprint out of danger. “Geronimo!” as well can take a little set up - a 5s Plunging Attack needs a cliff and a willing enemy at least.
One achievement requires defeating the “Unusual Hilichurl,” a new enemy without a lot of information confirmed about it at the moment. Rumours suggest it can be found underneath the tree at Windrise and on the hill south of Lingju Pass alongside a number of other unconfirmed locations.
Aside from the Primogem rewards, completing all of the Challenger - Series II achievements will also earn you a unique name card, much like all the other series. Good luck, and have fun achievement hunting.