The Admiral Butakov was to be the first ship delivered to India. It has been commandeered for the Black Sea Fleet.
https://svpressa.ru/war21/article/229309/
Engines, radar and missiles are the most expensive components of a warship. What you get from Russia is a floating barge and you have to do all of the work to make it combat capable.
I don't believe the deal is for $500m per as the media reported because the same deal cost $900m per just a few years before that. What changed from then to now that they could drop the price nearly 50%?
Why are they ordering more Talwars at twice the price escalation? This is a better ship than that, more capability, domestically produced and probably cheaper.