OSI, and the open source definition they produced, predate the very notion of public cloud by close to a decade. While you don’t have to accept the definition, you are out of step with the industry at large, who broadly use “open source” to refer to things which meet the OSI definition. There’s no need for a competing definition: it’s fine for software to not be open source.
As to the specifics of SSPL, I personally don’t see the rationale for accepting AGPL but not SSPL.
