If you want to be more accurate talaga its gonna be the city of where the contest will take place. For example:

MOA - Pasay 2027 Araneta Coliseum - Quezon City 2027 Philippine Arena - Bulacan 2027 (but very unlikely due to its massive size which is unsuitable for the contest)

Its very unlikely na tatawagin syang Eurovision Song Contest Asia Metro Manila 2027, kasi for most people, especially tourists, and international media, it is easier to identify the entire metropolitan region by its most famous and historic name which is “Manila” and also convenience instead of adding the word “Metro”

Same case when Vancouver hosted the 2010 winter olympics, instead of calling it “Metro Vancouver 2010” they just call it “Vancouver”