Sorry, if I misintpret your post, trying to understand Italian based on my mediocre Spanish
#XMPP itself does not define #e2ee, but almost all clients do support #OMEMO encryption, which is more or less copied from Signal.
In addition, you can choose a trustworthy provider, such a #cooperative or club.
Maybe for that reasons, German #police seems to believe (wrongly), that #Jabber (the traditional name of XMPP) were "the first pillar of #cybercrime"!