Research from Surfshark shows that the US, Canada, and the UK are at the top with anywhere between 5,500 and 6,000 titles.
However, recent data from Statista says that these countries have the most shows and movies:
Ireland (6,379) Malaysia (6,361) Indonesia (6,264) The Philippines (6,192) Canada (6,162) The Czech Republic (6,129) Singapore (5,960) The UK (5,954) Hungary (5,926) New Zealand (5,834)
You can also ask this on r/NetflixByProxy and r/NetflixViaVPN to see what other people have to say.