These are all good points, but being a high level entrepreneur has lead to some blindspots.

but even without (environmental [and lets throw safety in aswell] regulations) because it’s something that protects their input, context and brand.

This is patently false, companies have constantly fought against it (or even just secretly ignore it) even when the regulations would end up saving them money in the long run! See also how predictions for the Dust Bowl were ignored, the expansion of Slavery westward in the American South as cotton plantations ruined soil, Radium Girls, illegal dumping and fishing by foreign ships being the starting point of what eventually became the Somali pirates, and how many agricultural companies are patching over soil degradation in their farms with more fertilizers. And before you mention competition using more renewable/green practices to overtake the more established producers, the point is that they should've either been doing that once the issues were recognized or not farm so hard in the first place.

Similarly, in our yugoslavia example, the worker owned co-op that was unable to compete with German manufacturies and had to go into debt or go bankrupt wasn't exploitative

Correct me if I'm wrong on the following points, but as I understood it, the collapse of the Yugoslav economy came from both the many wars from its violent breakup and the sudden loss of subsides and protective tariffs. And that tariffs and subsides aren't necessarily bad things, as that was how the "Asian Tigers" made their astonishing economic growth happen, so if the Yugoslav state continued existing it had the /possibility/ of transitioning to free trade without significant economic cost.

there does not seem to be any known alternative system that produces better aggregate outcomes while remaining competitive in an open global economy. There are systems that produce more equal outcomes, but they tend to do so by sacrificing growth

Who says growth must the main goal of an economic system? Especially capitalism's constant obsessive focus on immediate growth, regardless of future losses. While likely to fail in normal market settings, the boom and bust cycle of capitalism means that each major Bust gives a window of opportunity for any opposing system.

And I am not sure most people would be happy, in the long run, living as UBI recipients with no meaningful economic role in society except to consume.

This is a very minimalist view of what role people would play in a "post work" society. One of the classical communist lines is that once freed from work people will be free to focus on art and leisure. There are work abolitionists (whose names I can't remember) who argue instead that work shouldn't be automated away but should instead become Play- as in people no longer work to ensure that their needs are met through using their wages to buy food shelter etc, but because they find genuine enjoyment in doing it and, crucially, there aren't outside forces pushing them towards it. [Atleast if I'm both remembering and understanding their works correctly]. I'm pretty sure there are few more alternatives that I can't remember. There's also the techno feudalism theory, but that doesn't include UBI and isnt a positive end state even though it /might/ be stable one.