While I agree with your pain points, I would not say XMPP that the protocol isn't any good.
- Pidgin: Just take a look at their bug tracker. You will not have any problems finding tickets requesting essential features which are 6 years and older (e.g. Message Archive Management). So unless the Pidgin devs get some done I would not use their client (Gajim is a much better alternative, especially since the 1.0 release last year).
- ejabberd OMEMO: Actually, I don't know what the ejabberd devs were thinking when they changed their default config to disable OMEMO. They told something about having a hard time tracking down issues with OMEMO enabled. Well, kinda makes sense from a developers perspective, but given the fact that OMEMO is end-to-end encryption, I wonder what they were expecting. Nevertheless, disabling OMEMO by default on the server is just a stupid idea.
- message delivery: I had problems with that too, but ultimately it was just a problem with some ejabberd setting (I think it was mod_stream_mgmt: resend_on_timeout: if_offline) [1].
From the user perspective, Pidgin is pretty much unmaintained at this point, so it's like complaining that old software isn't modern. Also, ejabberd doesn't disable OMEMO by default for quite a long time already.
And yet Pidgin is the go to client for people, especially on Windows.
When I got a MacOS machine up and running, I installed Adium (top result still if you go around looking for a MacOS XMPP client), also a dead project.
On Android, the top XMPP client does not support OMEMO and the new hotness XMPP client does not support OTP!
I have a legacy client on Android and Pidgin half hacked together with random plugins on my Windows boxes and I forget what in the world MacOS is running because I have it turned off half the time because the more clients I have connected the more problems I have and holy crap this is why Slack is a great product.
XMPP has had 20 years to solve these problems, and part of their problems of course is that the base protocol wasn't designed to solve these issues out of the box.
But, from the end user's perspective, Telegram, Signal, What's App, Slack, Discord, and Teams, all "just work"!
Actually, they still do (or do again?). Here comes the relevant part from their example config [1]:
force_node_config:
## Change from "whitelist" to "open" to enable OMEMO support
## See https://github.com/processone/ejabberd/issues/2425
"eu.siacs.conversations.axolotl.*":
access_model: whitelist
Oh, my bad - it was the default config in Debian package that got changed. I assumed it originated from upstream, but I was wrong and it's actually patched by Debian maintainer:
A large part about why there is a low availability of XMPP clients and why clients like Pidgin don't implement features for years is because of how verbose and, as OP said, much of a disaster it is.
- Pidgin: Just take a look at their bug tracker. You will not have any problems finding tickets requesting essential features which are 6 years and older (e.g. Message Archive Management). So unless the Pidgin devs get some done I would not use their client (Gajim is a much better alternative, especially since the 1.0 release last year).
- ejabberd OMEMO: Actually, I don't know what the ejabberd devs were thinking when they changed their default config to disable OMEMO. They told something about having a hard time tracking down issues with OMEMO enabled. Well, kinda makes sense from a developers perspective, but given the fact that OMEMO is end-to-end encryption, I wonder what they were expecting. Nevertheless, disabling OMEMO by default on the server is just a stupid idea.
- message delivery: I had problems with that too, but ultimately it was just a problem with some ejabberd setting (I think it was mod_stream_mgmt: resend_on_timeout: if_offline) [1].
[1] https://docs.ejabberd.im/admin/configuration/#mod-stream-mgm...