perhaps the problem is you're trying to fit computer in the wrong level of abstraction or projecting your position wrt to it incorrectly.

E.g. a computer may or may not be programmable for processes that live inside the computer.

This said, the compute abstraction is a logical gadget. Logical in the sense that it aims for consistency at a mininmum.

A logical gadget is a computer, by Curry-Howard correspondence.

This is a broad enough framework to explain why what you're debating against is the case: given that philosophy bridges language to logic and provies the framework for all sciences, seeing nature as compute is like saying there's a logic to nature.

So yes, everything is compute. Everything more detailed that that, turing machines, digits, whether it's it from bit or not is a separate matter of debate that may or may not be required.