I'm trying to connect from AR1893 USH-EZE 17:15-20:40 to UA818 EZE-IAH 22:05-05:15

Is 85 minutes enough connection time from domestic to international in EZE? As a small safety net, I've got GS on UA.

My other option is to take AR1897 USH-AEP 14:15-17:40. Which lands 3.5 hours earlier but requires an airport change.