Hi
I have an approved I 797 with my new employer B since 2019 and its valid until Jan 2021. I also have an approved I 140 from my previous employer.
Can I go to India or any other country for H1-B visa stamping?
Will any embassy give me an appointment for interview since I am not eligible for drop box
You can go to India for stamping but the issue is timing. January is only a month away. I would check ustravel docs https://www.ustraveldocs.com/in/nonimmigrant-visa.html?nodialog
Here is the info on applying in Mexico. I think you will see a lot of people who have paid the fees and waiting for appointments.