Re: no one has been able to invent new pronouns that sound natural as drop-in replacements
I agree with you that it seems cumbersome when you are talking about a specific person you know. But I was thinking the other day in fact, if you don't know the other person's gender - their name is hidden or not informative or whatever - it happens quite naturally. e.g. I would struggle to write about Boris Johnson using non-gendered terms, but if I was writing about "the prime minister" it would be entirely straightforward.