^ what Nick said is spot on. Aguja Guillaumet and Aguja De L’S are the two “intro” peaks in the Fitz Massif, and in today’s age are attainable by many competent and experienced 5.10 trad/alpine climbers. Aguja De L’S has two quite moderate routes on it, one of them, Cara Este, really only had one pitch of 5.10, the rest being largely 5.8/5.9.
There are also some “straightforward” routes on El Mocho that are popular during short weather windows.
After those couple options, things ramp up quickly in terms of scale and commitment.
The main thing is to have your kit dialed, be able to devour big approaches with energy to climb the next day(s), and move fast on alpine terrain and pitches up to 5.10+/11-. Pull on gear if need be - lean into that French free ethic :). The climbing movement is straightforward in Chalten, it’s not “tricky” climbing, but the routefinding, approaches, descents, and weather definitely are!
If you find yourself with time on your hands Dec-Feb, I’d definitely recommend the Patagonia climbing pilgrimage: Cochamo -> Frey -> Chalten