Completely disagree. International agreements have provisions that are applicable to local jurisdictions, but have many provisions that are just applicable to state or national governments (not city level). There is nothing in any agreement that prevents local authorities from their own legislating. However, and living in Taiwan or China as a perfect example, do you trust international bureaucrats that are often huge proponents of globalism, civil society, etc. or local devils? Taiwan often ignores international treaties when it does not suit them. Strong enforcement provisions is actually a good thing for a small business. Which leads me to your ISDS point. I will use my EU ambassador example again where I was co-presenting with her at a left wing university. Every question was about ISDS. ISDS does not really benefit big business. They can afford their expensive legal teams with or without ISDS. Let`s say you export recyclable bags and have lots of customers in China. You are an SME and your country has an FTA with China that has ISDS or another form of robust dispute resolution. The Chinese are enacting all kinds of barriers that could effectively shut you out of the market and bankrupt you with expenses. Do you trust their court system or an international panel chosen based on their legal backgrounds, international experience, and globalist outlook? ISDS would be your greatest friend as it could resolve it quickly at minimal expense and bypassing a legal system that is stacked up against you.
Your view of corporations belongs in the early 20th Century. They are progressive these days – much more than local businesses or corrupt sub-national governments that often cut corners, do things on the cheap, and prefer local and outdated ways of doing things.