not to go too far off topic but singular they does have a history of use for hundreds of years, but the current usage as demanded by some non-binary folk is different than the historical uses. It was historically used to either refer to a person of unknown gender, or to optionally refer to a person of a known gender. so your options for singular pronouns might be either he or they, or she or they. But historically (as far as I can tell) no one has ever demanded to be referred to solely by singular they.

If you couldn't tell, I don't like demanded singular they prnouns very much. I have no problem calling a transgender person by their expressed gender, and I will refer to a person with they pronouns if they ask but I will secretly think that they are a jerk for requesting people do this thing.

And finally, no, expanding latinx to people who don't want to be labeled as such is exactly the point of this thread because latinx was brought up just talking generally about the Latinos.