Grinding MMORPGs is not the half of it.
I recall that the most popular game in Korea is Kart Rider, playerbase 6 million(of a country of 24 million). Obviously a racing game. There are some extremely popular FPSes, including CS2 and a Korean game named SuddenAttack. I'm just telling you that MMOFPS's are quite viable over there.
For a combination of grinding and FPS, see Gun.