You should look at relativism more generally, and epistemic relativism in particular https://plato.stanford.edu/entries/relativism/#EpiRel
If you hold everything is relative, you have to deal with apparent universals, like geometry and mathematics. The persistence of objects & systems in influencing people whether or not they accept their reality, is also an issue.
Individuals don't exist, for physics, they are a conceptual shorthand for a certain lump of complex chemistry. So who do things really get to be relative to? Substance dualism, implicitly taken up by many scientists, holds a concealed 'mind of god' perspective, that will be the ultimate arbiter of what is objective.
These problems and others, like the Private Language argument, are resolved by considering intersubjectivity. This way of thinking is something like a peer-to-peer reality, with widely taken up behaviours altering how the whole system functions. Language makes humans highly networked in their reality-making. Claiming ontological relativism without limits, ignores that and risks becoming a form of solipsism.
