I'm Indian and I do use EN-IN, as do scores of people using devices sold in India that have pre-installed and pre-configured Windows.

If using en-in is as unpopular as you suggest in India, then surely it’s non-existent outside of India..

I use en in too. Better with autocorrect in phones and computers

Not true mate. Have setup plenty of machines with this as the choice and have also seen others running with ENG IN as the layout in their off-the-shelf laptops.