The Vietnamese took a beating and also their pound of flesh from the Chinese. The Chinese military of the time was not in a good state and took heavy casualties for what they actually did to the point it made the Chinese very, very nervous about a future fight with the Soviets with their current military. Sure, they weren’t operating with their air force, but they didn’t exactly do well either. The Sino-Vietnamese war was a bit embarrassing for both sides. It cost quite a bit for a punitive expedition, and the Chinese didn’t force the Vietnamese to abandon their nation building in Cambodia, really a big part of the Chinese hopes with the whole thing. Vietnam didn’t get the stomp they were hoping for and had to cede some territory. It’s honestly a draw.
Delaying the withdrawal was both a good idea and a risky one. I don’t think any withdrawal was going to be smooth from Afghanistan. If the ANA didn’t fight for Kabul now, they wouldn’t have fought for it then. There were and are lots of mistakes made with this whole process, which compound on mistakes made months, years, and decades previously. It’s a massive convoluted mess of a conflict and I don’t think that Afghanistan will be peaceful any time soon. If that comes out as simping for Biden, fine. I don’t feel any one mistake in any of this can be pointed at as the worst fuck up of all time in Afghanistan. There’s so many moving parts in all of this that it’ll take time before any objective take on much of this can be done. Opinions are opinions.