Very simple rule:
If a road is part of a National Route system (quốc lộ), then the Ministry of Transportation (Bộ Giao thông vận tải) is responsible for managing it, so any road upgrade will be done by the ministry. If it is a local road then either the People Committee (Ủy ban nhân dân) or Department of Transportation (Sở GTVT tỉnh) is responsible for its update.

In 2011-2015, the Ministry has upgraded the whole route of Dầu Giây to Dalat (including the Prenn Pass), but the recent upgrade in 2023 was done by the government of Lâm Đồng province. Isn't that clear?