Need Information regarding US Visa application

A friend is an Indian citizen. He is on a valid H1B visa and will be extending his Visa. It's impossible to get Visa drop -off appointment dates in any US consulate in India. He needs information on which other countries can he can apply in.

He has heard that Indian citizens are going to Malaysian US consulates and applying for visas there since wait times are better. He is happy to travel to any third party country as long as 1. They have a relaxed visitor visa policy for Indian citizens visiting (like visa on arrival/online application of 30 days visitor visa etc.) 2. it should be easy to get an appointment for Interview waived Passport drop-off around Feb 2023.

He is open to countries like Thailand/Indonesia/Singapore/Oman/Malaysia/Cambodia etc.

Need help to research through US consulate websites, visa related forums online and different countries' visitor visa regulations to determine which country would be the best fit.