Yes, gods are different in different religions, but why would you, to determine whether something is a god in christianity use pagan standards?
My point is, that within the logic of christianity you can not say there is more than one god, it is unreasonable to say that christianity is polytheistic.
Also, “one divinity appearing in multiple forms” is not a polytheistic thing, since you only have one divinity. The trinity does not consist of three gods, but of three hypostases of the same god. My point is that it can only seem like those are three gods, but if you have more deep knowledge of christianity you will never say that.
If you say chickens are only valuable because they feed humans, you are admitting they do not have any intrinsic value.
You are misunderstanding the meaning of the word “value” in this context, you almost use it like monetary value, but this is not accurate.
Also, we are not talking about value for someone, but value for itself. A human is valuable not because he is useful, but for himself. Even Aristotle said that the difference between a free man and a slave is that a free man exists for himself while a slave exists for others. By that rationale, not recognising intrinsic value within oneself but instead viewing ones value in terms of your worth to society is slave mentality.