> I would either support all kinds of countries markets, or focus only on the US because there will be lots of resources online that help translate US market knowsledge to a specific country's.

Fun fact, India's public accounting for corporates actually mirrors the European standard in this regard (IFRS), so on a corporate level, it's very similar. On the other hand, the US follows GAAP Standards, which are different in a number of significant ways.

Apart from that, there's very specific knowledge for the Indian markets, specifically the prevalence of otherwise globally very niche financial instruments like chits or actual gold, or the prevalence of insider trading and a general lack of regulation on that front. Although I'm seeing a lot of strong development on that front too.