One of my languages has three genders for living creatures, and two genders for items. Those genders are all different from each other: humans and other living beings are male/female/living neutral, things are item neutral/item neutral. An item neutral plural is also used for groups of living beings, but not for all groups of items.

One item neutral singular can in some instances be used for a living being regardless of their gender. The other item neutral would be insulting if used about living beings, and especially dehumanising to humans (wish someone had told me this sooner).

I have no idea when to use which item neutral. Locals keep correcting me or almost imperceptibly wincing when I get it wrong, so when I want to sound more fluent I just use the item plural for singulars as well - it seems less annoying for some reason.

Oh, and for one of the item neutrals, if you accidentally use the other item neutral it means the plural of the first one. Kill me now, lol.