Vietnam has "Three No's" defense policy that will preclude any substantial anti-PRC alignment. There's some wiggle room to posture / hedge with US for theatre in new white paper, but nothing major because the "Three No's" were specifically drafted in 98 after normalizing relations with PRC with appeasement in mind. The war and subsequent border skirmishes thoroughly deindustrialized North manufacturing and set back VN development for decades. VN could have gotten on the export-driven gravy train much earlier, instead it went to PRC. There's very little chance VN will embrace western alliances on tier of PRC/RU "comprehensive strategic partnership" because PRC build up a lot of leverage over the years, including funding (frequently owning) a lot of the supply chains in VN, and via control of hydropower/water/agri resources by influencing upper Mekong Laos. Both Trump/Biden admin have tried to court Vietnam somewhat informed by spurious sentiment that "Vietnamese public hate Chinese, therefore they must be onboard", but went nowhere. TLDR is PRC has a lot of existential leverage over VN, which provides leverage over SKR ontop of existing SKR economic leverage.