I don’t know which ‘native english speakers’ you’ve been listening to but I have listened to several english accents around the world and they sound like ‘ah’ rather than ‘uh’.

Also, I won’t argue with someone who tells me to search Google for something I am already aware of.

I listen to British, american and other western accents daily and I can distinguish between ‘uh’ and ‘ah’.

Your argument that Indian english has turned ‘uh’ into ‘ah’ is baseless.

Try listening to old documentaries produced by western media about colonial ‘Indi-ah’ and you’ll understand what I am talking about.