Paolo I have a lot of sympathy.
I've become very interested in how to improve listening skills because I notice that some of my students really struggle with it. I myself find listening the most challenging aspect of language learning.
One issue with listening that is often not mentioned is vocabulary. If you don't know a word you're not going to understand, especially if that word is crucial to the meaning of the sentence.
On this forum you will hear the same old advice that you should watch movies with subtitles and listent to podcasts. These things are helpful, but from my own experience I'd say that they are not enough. I've found the most useful thing is to use these souces with a native speaker exchange partner. When I can't hear a particular word we stop, go back, and my partner will then explain just what was said. Then I practice saying it myself. It can be a vocabulary issue, but often it's the accent, or the speed that cause the problems.
Good luck with improving. It does get better, but it can be a slow process.
You're spot on, Ramona, at least in my case : I articulate [silently] the text when reading, even in my native language, and try to visualise it while listening [to another language], and also when preparing to speak.
I've tried 'speed-reading' or skimming, but find it unsatisfying, and often have the feeling that I've missed something. Listening to a language I am trying to learn, and not being able to follow all of it, gives me the same feeling.
When you read slowly also in Italian I would recommend to practice in Italian first. There are techniques to speed up both reading and listening which you might need to practice in your native language first before you return to English.
One significant reason for slow reading is when you move your lips and/or tongue whilst reading as if you were silently speaking. The problem with listening might be that you're trying to visualise the spoken words which would also take too much time to follow the spoken word, but that's just a guess.
I understand and sympathise with your situation as I also experience this difficulty, in my case in Italian. There seems to be very little material produced for those who have not yet acquired the facility to follow natural speech, even in online videos made for language learning.
Additional skill is required to 'disentangle' [districare] spoken words so they can be identified, and this is only acquired through extended experience - the reason why listening competence often lags far behind a learner's level of writing. Those of us who are not regularly or routinely exposed to the spoken language will take longer to 'tune' [sintonizzare] our ear than those who are immersed in it.