honestly, i think it mostly depends on the pronouns itself. however lets take an easier to start w neopronouns.
i have a character that goes as "mew/mews/mewself" it has another set of pronouns so i might use he/it out of habit, but since im used to using thoses it will be easier for me to explain lmao (mews catgender btw)
if you had to remplace pronouns w neos it would be:
He/His/Himself to Mew/Mews/Mewself, and in sentences it would be:
"He doesn't like dogs" to "Mew doesn't like dogs"
"This is his chair, you can't take it" to "This is Mews chair, you can't take it"
"He finished his drawing, and is very proud of himself." to "Mew finished Mews drawing, and is very proud of Mewself.)
i hope that makes sense lmao, they are confusing at first but you slowly get used
