Based on my reading, Active–Stative languages typically feature the core arguments of Agent (AGN) and Patient (PAT). While the precise rules differ by language, it seems to be that for intransitive verbs, the sole argument will take one of these forms based on a quality such as volition, e.g., "I jumped" would mark the subject as A as in "1sg-AGN jump-PST" as jumping is intentional, while "I fell" would mark the subject as P as in "1st-PAT fall-PST" as falling is not intentional. For transitive verbs, the argument that shows more agency would take A and the other one P, e.g. "I ate the cake" might be "1st-AGN cake-PAT eat-PST". An adjectival predicate might be expressed as a stative verb, e.g. "I'm cold" as "1st-PAT cold-PRS".
My question is how do such languages express nominal predicates as in "I am a person"? My being a person requires no volition, so shouldn't take A, but that would leave two PAT arguments, which as far as I understand would seem to be ungrammatical. Do such languages use techniques such as copula affixation (essentially inflecting nouns like verbs) or other syntactic structures to express these kinds of predicates?
Any examples from how Active–Stative languages handle these kinds of expressions would be really helpful. Thanks!