Apps and maps.
Viewranger offers no coverage for Chile and Argentina. Sounds like Gaia GPS is best for those nations.
I can download Patagonian maps and use them offline on the trail.
Gaia GPS is free to try for a week. Subscription membership costs $19.99/year while a Premium Membership is $39.99/year.
I joined the lower tier plan hoping the additional maps would help in South America. For Aconcagua Park, Argentina, for example, none of the layers are much good aside from Satellite with Labels. You can see the trails clearly beside water sources, tents, etc.
I’ll try it when I get there in a week or so.
Gaia claims to be superior to AllTrails in most regards, as well. And less expensive.
besthike.com 
Hello! Am going soon to Patagonia as well (Chile and Argentina) and found your post about the Gaia GPS.. How did it turn out? Would you recommend it?
Thanks for your help and all the best! Goran
I can’t say. I ended up using Maps.me instead.