Agreed. South Korea don't have many systems that China have already developed in the 70s. They don't have a competitive domestic aircraft engine program. Their space program is pitiful compared to China. Their drone program is also pitiful compared to China. Nevertheless, whatever gaps they have right now, they are importing it from Western suppliers. While dependency on the West is not a great thing in a real war, it still does mean that South Korea can get its hands on some good stuff in peacetime.
South Korea has a successful ground vehicle program. Say what we want about it, but it is very competitive vs the best Western manufacturers. The South Korean naval program however is where they are quite formidable. While extremely dependent on Western key component supplies, the South Koreans are one of the best shipbuilders in the world. They can build some formidable naval vessels like their large Aegis destroyers, LHDs, and some very modern SSKs. Their latest SSKs are reportedly capable of launching their Hyunmoo-4 SLBMs.
I'm not worshiping the South Koreans for the achievements, but we have to at least acknowledge what challenges they are able to bring to China and work out some counters against it. North Korea is the declared target of the ROKN. But is it really? The North Korean Navy is vastly overmatched by the ROKN. What if South Korea suddenly decide to pivot their navy against China? While small compared to the PLAN, the ROKN can pose a serious headache in the ECS, and are situated at the entrance to the Bohai Sea. The ROKN also have long range land-attack weapons like the Hyunmoo-3 LACM, and Hyunmoo-4 SLBM to further add to the anti-missile defense burden of China. Can the PLAN destroy the ROKN? Absolutely. But it would still consume some significant resources to do so. And it would be unwise to underestimate ROKN.
So, my point is that, we should consider the South Koreans as a potential adversary like Japan already is, in a potential US-led war on China. South Korea is not India, we should expect them to be a competent force backed by a competent industry. Keep them in mind and don't underestimate them. Or I could be entirely wrong, and maybe South Korea might actually stay out of a war with China. But there is that rampant Sinophobia in South Korea, and the Yoon government, increasingly aligning his country with the US and Japan.
