I think the a major component of the blockade is that one they begin to capture or burn ships, the insurance rate goes way up. Once the ships become even slightly more costly the margins go down. Once it is even possibly unprofitable to use the straight, they will have effectively created a blockade.
I think the NUG has many elements within it that are from the former, US-captured, National League for Democracy, and its formation was a coalition aimed at bringing on board the various oppressed nations that have been struggling for independence for decades, the political elements of the former government, generally representing pro-western liberals and national bourgeoisie types, were essentially left leaderless, because the Aung San Suu Kyi clique had become centered around her personality and almost directly administered by her associates who often times were foreigners or outside of Myanmar until the so-called democratic reforms had come about.
That being said, it is unclear to me, from anything I have read, where leadership truly lies within that coalition. Most of the principle armed groups with experience were from the Shan, Karen, Kachin, Mon and other nations who have been fighting for decades for self-determination, often with a long history of very radical social platforms. The Burmese Communist Party has even re-entered the country from Yunnan and are allegedly fighting in the south, I believe they were armed and trained by the Kachin Independence Army… they are in an area this map labels as the PDF and are often labeled as allies of the PDF… Are they also working at the behest of the CIA? It’s not impossible but seems unlikely…. It also sounds like China’s stance of non-interference, that is often thought of as pro-junta, is sort of out the window. They have likely been arming and providing support to some of the groups on their border, like the Shan, in exchange for combatting illegal human trafficking schemes that have direct toes to the junta. At least that is what we know publicly. I would imagine that there is more going on than China will ever admit to, but this seems to be a signal that China is unhappy with the junta and that China mostly desires a stable political situation across its border.
China has been put in a difficult position by the coup in 2021, which I think was an opportunistic play by the military. They saw the new cold war between the US and China, while also seeing their prospects for their own political leadership dimming, so they took advantage of the moment and seized control. Neither side can play too direct a role in the conflict without risk of it blowing up in their face, although the US does have an advantage because an unstable Myanmar on China’s border is something the US might desire. But the junta is essentially pro western/neoliberal, with almost identical politics as the Aung San Suu Kyi led NLD. It really is difficult to say what the character of the civil war is, in part because there are contradictory elements within it. I agree though, anyone calling for the “international community to step up” which is a phrase i keep hearing verbatim, seems sus. Many of the more left-wing elements in this civil war should be fighting for total victory over the tatmadaw, but a UN brokered agreement would likely just mean restoring the old system or liberal democracy without any promise of political autonomy or national liberation being addressed