...morality, by definition, is the code of behaviour of an individual, not a community.
So it would be erroneous to describe a community as acting "immoral" for, as an example, building a wall or legalizing abortion? The correct word would be "unethical"?
You can refer to a person as amoral or immoral. You can even refer to a community as amoral or immoral (in that everyone in the community is lacking morality).
But, the word to use when speaking of a community standard is unethical, yes.
I don't share your view, but I'm willing to be persuaded. Perhaps you can provide a link to a scholarly source that can corroborate your definition.
In my view, morality is universal and it comes from God. It is what we inherently know (or should know) to be "right" and "wrong". That which is "immoral" is that which goes against God. In my view, both an individual and a community can be acting immorally.