With the same line of reasoning you can argue (and some have) that numbers aren’t fundamental and are only made up by humans. In my view, the number of swans in the pond is three whether humans exist or not.
Meanwhile temperature (for example), while physical, is a statistical property of a macroscopic system. It isn't fundamental - rather it's an abstraction over a (very) large set - but it is nonetheless a quantification of physical characteristics. Whereas a number, for example 2 rocks, is not quantifying any physical property of the individual rocks themselves.
Fundamental physical properties don't depend on other members of an arbitrary set as determined by an observer.
> at least as much as temperature is
But here I've been explicitly claiming that temperature isn't. It is a statistical abstraction over a physical property but it is not itself a physical property in any inherent sense. That's ... kind of the entire point I've been trying to make about an entire class of concepts.