Multinational corporations are, I suspect, an artefact of a policy environment in which a broad range of loosely aligned policy makers & politicians around the world create capitalist incentives out of self-interest (which they might perceive, in an ill-advised fit of optimism, as general interest).
The impact of these multinational corporations is seldom if ever 'mostly positive' for society. For every wealthy shareholder or happy elite customer, they usually demand many exploited children or menial labourers to extract or create the resources. These are often invisible to those who benefit.
I would love the NZ Green party to become the non-corporate party. Not anti-corporate, just intentionally avoiding any favouritism towards - or dependence upon - any multinational corporations (whether originating in Aotearoa or without). That, of course, also means no subsidies and zero tolerance of non-payment of fair taxes in Aotearoa.
This is justifiable, I think, because the NZ Green Party's stated values - https://www.greens.org.nz/our_values - are largely incompatible with the inherent behaviour of multinational corporations, driven as they are by their single incentive (their only 'principle'): maximise shareholder value.
Public multinational corporations are really just 'engines of inequity'. That's what they exist to do: take from the many to give to the few, by whatever means necessary.
Suffice it to say, I do not think that the world 'needs' public multinational corporations. Not even a little bit. They were arguably useful in the past, like before we had widespread rule-of-law, decentralised and reliable global communications, advanced logistics, and commoditised paths to market. But today, like that cute pet alligator that rapidly grows too big for the tank and then the swimming pool, those corporations have turned the tables on humanity - we serve their goals, not the other way around.
This will be awkward for some members of the Green Party who are employed by such corporations and contribute their intellectual and social value to them as they make the world worse every day. For those people, I'm afraid I can only encourage them to read up on 'cognitive dissonance' and reflect on important life decisions in their own time. Because cognitive dissonance can be exhausting.
I think, though, that enough people understand (or could be helped to understand by a compelling political movement with eloquent and inspired leadership) the threat multinational corporations pose in terms of their direct actions, e.g. disproportionately affecting our biosphere as well as our digital and physical society - our Commons - for their own private self interest. I think such a party could gain quite a bit of sway, especially if it could show the alternative approaches to organising communities and defining a different sort of prosperity, perhaps something like "the policy of enough", that many would find compelling. I'd like to see us test that, as a nation.