Some will want you to use both sets of pronouns alternatingly ("she asked me to come over, but i was busy, so i asked them if we could postpone")
that sounds exhausting both to insist on and understand compliant usage of
-someone who doesn't bother with "they" irl because it's so burdensome to tell and correct other people
i meant that it makes sequential sentences harder to understand when reading or listening. like the occasional singular-plural ambiguity with "they" but much more severe since you're using multiple different pronouns to refer to the same subject when normally (and unlike they, where we had an informal singular all along), changing pronouns heavily implies changing subject. Someone who feels really strongly about being referred to with rolling pronouns like that should write a book or long poem using several of them that seems like it's about multiple people but is actually about one. "art" heads would eat that shit up.
also, i'm not so sure that conjugation is the same mental process as word substitution, but that field isn't my expertise.