my issues with element x are with the client itself, mostly missing features and bad UX. the main reason I don't want unified push is, it's just yet another thing for me to install and maintain, plus all my users need the client app installed. the ntfy server app even defaults to having a full web interface, fortunately it's possible to disable but it's just so much stuff to replace what used to be built-in to the app, to supposedly solve a battery life problem that I've never experienced.
I'm still going to get around to it, because element classic will be deprecated eventually. one of my users is on iOS and has a well-known bug with images not loading, which will probably never get fixed because they're focusing on the new client. and unfortunately I do have users that expect voice calls to work, so it sucks to hear that'll be annoying too.