If your opinion is based on concrete experience, you could help people understand your position by sharing the specific aspects of XMPP that you dislike. An opinion without evidence or reasoning is not a valuable contribution to the conversation.

It's been well over 10 years since I worked with, almost 15. I remember issues with keeping multiple devices in sync, syncing them back up when a user comes back online, especially with multiuser chats. I understand that is probably better now, with carbons and archiving XEPs.

In general, it felt like, XMPP has too many "optional" features. The core protocol is tiny, but everything you need and want to make it useful is optional.

My opinion: XMPP is too little like Matrix (e.g. decentralized rooms, people as verification targets, messages (incl. e2ee ones) easily synced to all sessions) while Matrix is in a sub optimal state due to the Element/Element X client split