US Immigration from Argentina

Hey guys! Here is our background information. We were married September 16th, 2017. My wife's green card was issued February 13th, 2019 and it expires February 13th, 2021. I believe we should file the I-751 90 days before her green card expires correct? Anytime sooner and it could be rejected I read somewhere. Also I just wanted to confirm that we should be filing the I-751 and not the I-90. Both seem similar. Thank you for your help!

I live in Cordoba and have my interview appointment September 17th and doctor appointment September 15th. I asked the embassy and it's been 4 days without response, I have been searching EVERYWHERE (Buenos Aires government, Cordoba government, COE in Cordoba, sites, etc) and calling and sending emails to everyone I could think of but nobody says anything clear. I'm so close to giving up and changing my appointment to another date but my husband contacted the Argentinian consulate in the US (just for useful info) and they recommend against changing the appointment.

I plan on going to Buenos Aires and stay there to quarantine if necessary and until I can get the visa and can go to the US.

The doctor said she can give me an appointment ticket to show to the authorities but I still don't know if I need to quarantine there or what other permits I might need.

I know I have asked many of you here already, but any info you have is appreciated.

Thank you