I can only speak to my personal observations.
Hermès in the US seems to be most popular in big cities, and in the more monied parts of those cities, and their vacation spots (NY Upper East Side/the Hamptons, Beverly Hills, Palm Beach, etc.). These places are raining Birkins and to a much lesser extent Kellys. Evelynes PM and TPM are very popular day bags. In NYC it’s 30 and 35 cm Birkins, in LA it’s 25 and 30.
In the UK I’ve never seen a Birkin outside of London unless it’s at someone’s country place, so very much the same as in the US. But Londoners definitely carry Hermès. It is not all tourists. I don’t see a lot of exotics in London and tend to see classic colors, Gold seems really big in London. I see a lot of non B/K bags like the Roulis or Bolide in London.
In France, again, same, mainly in Paris and parts of the southern coast, but definitely a bit more classic colors and tons of black, I rarely see, say a Lime bag except in the south. I see more Kellys in Paris than in most cities, and again, lots of the under radar bags. Hop to Monaco and it’s all Birkins and Kellys, usually small ones at night and medium during the day, and so many exotics!
Big East Asian cities are the same, Birkins and Kellys, but the bags are smaller and brighter colors. So many mini Kellys esp at night!
In the Middle East it’s raining Birkins again, more Kellys than in the US but still mainly Birkins and I mostly see small and mid sizes (25, 30 Birkin, 25, 28, 32 Kelly). Dark colors for day and I see more brights at night, also a ton of exotics.
In Russia I mainly see Birkins, and usually at night or inside, like in a restaurant, as opposed to seeing as much street eye candy. B30 seems really popular. And definitely exotics at night.
Epsom and Togo seem popular everywhere. Box shows up usually on the more formal dressers. I have almost never seen Barenia in the wild in a B or K, which is fine by me - more for me!