Oh I love rankings!
I've only been watching BLs since autumn, so my ranking would be a little different.
1. Thailand (The holy Godmother BLs, responsible for all the Stereotypes, the good ones and the bad ones.)
2. Phillipines (Has made at least 2 Outstandig BL-Dramas in 2020 with great support for the LGBT-Community.)
3. Taiwan (a little bit more serious and realistic than the other ones, has those their own charm)
4. Japan ( Don't make enough BLS yet, but those are highly recommended)
5. South-Korea (Are still in the Beginning Era of their Own BL-History, hope they will make a full standart BL-Drama in the near future.)
6. Vietnam (Unfortunately not supported on MDL, have they at least 7 or more BLs and will produce a lot of content in 2021)
To be mentioned is that Cambodia, Myanmar and Laos are making their own BLs in 2021.
Since China has banned gay content i wouldn’t rank it.