Are how these characters are pronounced in the Hindi course even how they are really pronounced?
The differences are incredibly subtle, sometimes "k" and "g" sounds exactly the same when spoken by the bot, "a" and "ā" sound like they can be used the same way on their own because i'm not given context to why they are used different and how they sound in words. The "ā" sound doesn't even sound like it is different in duration to "a" so can somebody explain to me?
I would say that save for a few bugs here and there, the bot's pronunciations are mostly correct.
The क(k) and ग(g) sounds correspond exactly to the 'k' and 'g' sounds in English. Both sounds are articulated from the same place but 'k' is unvoiced and 'g' is voiced.
The vowel 'a' is like in 'alert' and 'ā' is like in 'far'. I can see how it might be difficult to distinguish the sounds when the vowel is sounded in isolation though.
I once read that long vowels in Hindustani were vestigial remains from Sanskrit and were pronounced as short vowels nowadays. I think it was in the Assimil collection, not sure how true that information is though.
This is not true. Longer vowels are pronounced as long and short vowels as short in both Hindi and Urdu registers of Hindustani. For example, 'kam' means 'less' and 'kām' is 'work'.