Happy to hear this is going to happen, but I'm very unsure if SG048 will be successful. There are so many hurdles they will face in Vietnam. Vietnamese are not so fond of groups, especially girl groups. The ones active today struggles and when you have a group with 20+ members... I'm very skeptical but we'll see.
Sure the market is so used with soloist, but who know the young audiences may give it a chance. I think Vietnam just very bad at marketing the group to be appealing, attention grabber that can make industry/audience to talk today.
First most probably shock with this group and even gain antis (Lmao), but it make people talk. I mean I don't think Indonesia has an idol group culture either? Their culture is even extremely conservative (Vietnam's culture is consider way much more open than them) but the group ended up doing quite well. And same with Thailand... All of the youth from these countries have in common is that they all consume Kpop for idols. So there is a demand/chance if it actually provided good marketing, concept, content and PR to targeting audiences.
Even China that also predominated with soloist, balled and ost have some successful idol groups now (and there were many flop be4 that happened). Korea and Japan are the only Asia countries with long, establish, open market for groups (Taiwan used to be a long time ago, and Vietnam used to have successful bands in early 2000's too), the rest are all dominated by soloist and probably with some bands that played instrument. Local idol groups are all met with challenge in their own country.
And I think they don't have to appear with all 25 mems when they at public, but send a smaller units instead to promote the group. Only for fan events and such, they can appear as a whole.