

Using “they” for a singular person has been used since at least the 14th century, so there’s no need to feel uncomfortable with it. I highly recommend reading the Wikipedia page on Singular they, which touches on its history.
A similar example is “you.” “You” used to be only a plural, with “thou” being the singular, but over time it fell out of fashion and now “you” can be used as singular or plural, like how “they” can be singular or plural.
Singular “they” was criticised by some people hundreds of years after it started being used. But language cannot be prescribed; it is determined by how people use it.

Oh that makes sense, sorry I misunderstood!
Yep, they/them/theirs is used in the same place as he/him/his or she/her/hers. It/it/its should not be used for people unless someone explicitly says those are their preferred pronouns. “It” is typically used for objects and non-human animals, so it could be seen as rude to refer to a human as “it.” If unsure, use they/them.