I do know the difference between 2nd & 3rd person pronouns. I am also aware that Shakespeare did use the singular “they”; however, it was only used when the gender was not prefaced. “whosever knows the answer shall let themself in” . However, in the 21st century cases, self labels of random gender of 3rd person singular will only lead to further confusion. There are better options if people want to avoid gender. According to Dennis Baron's Grammar and Gender:

In 1789, William H. Marshall records the existence of a dialectal English epicene pronoun, singular "ou":

"'Ou will' expresses either he will, she will, or it will." Marshall traces "ou" to Middle English epicene "a", used by the 14th century English writer John of Trevisa, and both the OED and Wright's English Dialect Dictionary confirm the use of "a" for he, she, it, they, and even I.”