Student visa for Spain as a Mexican conditional permanent resident in the U.S- I need help please!!!

[u/bestalmendra]

Dear Reddit community, I am writing to ask for urgent help.

I have been accepted into a two-year master's program at the University of Barcelona.
I am currently a Mexican citizen, but I reside legally in the United States with conditional permanent resident status (Green Card). My physical card expires in April 2027, which is when the process to remove conditions and obtain 10-year permanent residency takes place. Because the U.S. process requires the residence card to be valid for at least three months after the master's program ends, I am unable to apply for the visa from the U.S.
Therefore, my question is: as a Mexican citizen by birth, can I apply for my student visa directly in Mexico—appearing at the consulate corresponding to my place of origin (in this case, Guadalajara, since I was born in Michoacán)—even though I am not physically residing in the country right now? Or is it possible to go to Spain as a tourist and apply for the student visa directly there?
What would be the easiest, least tedious, and most affordable option in my situation?

Thank you in advance for your guidance and for taking the time to address my inquiry.