Just for the heck of it, if you heat protein enough to denature it but have no Maillard reaction (let’s say you’ve just steamed an egg or something), would that not be considered cooking by that definition?

My understanding is that denaturing is a physical structure change, not a chemical one (and according to Wikipedia can be reversible in some cases), not a biochemist or food scientist though so totally accepting that my understanding is incorrect/incomplete.