Sure, but I don't think that's what this paper and other similar ones are saying. I agree, of course, that things like programming languages or algorithms or even logical circuit diagrams are abstractions, obviously. But they are abstract descriptions of a real physical process that happens, for example, inside a CPU - in exactly the same way that an electrical diagram is an abstract descriptio of a real physical process that happens in an electrical circuit, or a thermodynamic calculation is a description of what happens inside an engine.

But the engine, the electrical circuit, and the computation inside the CPU are objective realities. There could be many other ways to describe and characterize the same physical realities, of course, but that doesn't make them observer-dependent phenomena.