Therefore the Hyundai workers here on b-1/b-2 visas would be allowed to work for the company factory in the US given they were actually paid by the Korean company

The B-1 and B-2 visas are visitor visas intended for business visitors or tourists, respectively, and do not authorize employment in the United States. According to ICE statements and multiple news reports, individuals on these visas are not permitted to work in US-based companies.bbc.combbc.comICE raid on Hyundai plant in Georgia swept up workers on visitor visaskoreaherald.comkoreaherald.comImmigration raid on Hyundai-LG plant in Georgia: Here's what happened

The Korea Herald specifically notes that while the B-1 visa may be used for activities such as staff training or installation/maintenance of machinery, actual construction or factory work is prohibited, and wages cannot be paid by a US entity.koreaherald.comkoreaherald.comImmigration raid on Hyundai-LG plant in Georgia: Here's what happened This implies that even if payment comes from the Korean company, working physically at the US factory is not allowed under these visa categories.

The recent large-scale immigration raid at a Hyundai plant in Georgia targeted workers on visitor visas who were found working illegally. Over 450 workers were detained, many on B-1/B-2 visas, indicating that their presence working at the factory violated US immigration laws.abc.net.auabc.net.auSouth Korea announces deal to bring home hundreds of Hyundai workers detained in...cnn.comcnn.comHyundai plant ICE raid: What we know about the agreement for detained South...+2 more

The fact that South Korea negotiated a deal to repatriate these workers rather than legalize their work status further supports that their employment was unauthorized.washingtonpost.comwashingtonpost.comSouth Korea announces deal to repatriate workers detained in Hyundai raidapnews.comapnews.comSouth Korea will bring home 300 workers detained in massive Hyundai plant raid...+1 more