What do you mean? Unless you're using a very old client like pidgin, this stuff shouldn't be a problem.
Not sure what that even means. Worth reporting.
> pictures are a link to the server, so I have to manually download them all.
I think you need to install the image preview plugin.
For gajim make sure it's a recent version. Dino-im https://dino.im/ is decent. poezio https://poez.io/en/ if you want a text client. converse.js https://conversejs.org/ for a web client.
Public server wise I don't have any recommendations (but i'm sure others have plenty) other than movim. https://movim.eu/#try they have a baked in client (and do a whole bunch of other stuff like micro blogging) but once you have a account, there is no reason you can't use any client you want.
Encryption with omemo is a issue and usability could be improved (I believe people are working on that).
EDIT: featured on HN https://news.ycombinator.com/item?id=16948597. Look at the comments and you understand why I'm not the only one thinking, the UX is bad...
then we could see an estimated total, like for $xx we could get most of these apps all on the same page of features running... if that is the major hurdle - a crowdsourced money or and time to get them all modernized may make the whole ecosystem 2.0 and worthy of use?
Surely it can't be that much that is needed - yet it seems that fixing just one or two is not having the same network effects of having them all speaking the 2.0 feature language.
The worst thing isn't that the standard isn't defined or something, but that a lot of projects are claiming to support XMPP when they only support some core functionality...