I am not privy to specific details, but in general there is a difference between investment and partnership. If it's literally an investment, it can either be in cash or in kind, where in kind can be like what MSFT did for OpenAI, essentially giving them unlimited-ish ($10b) Azure credits for training ... but there was quid pro quo where MSFT in turn agreed to embed/extend OpenAI in Azure services.

If it's a partnership investment, there may be both money & in-kind components, but the money won't be in the context of fractional ownership. Rather it would be partner development funds of various flavors, which are usually tied to consumption commits as well as GTM targets.

Sometimes in reading press releases or third party articles it's difficult to determine exactly what kind of relationship the ISV has with the CSP.