I don’t have any suggestions for helping you visualise, but I would suggest that you have a think about whether you need to visualise.
Not everyone is that kind of reader.
I read a lot and I only visualise if it is clear that the author is explaining something where the physical look or position of things is actually essential to a plot point that I need to understand. In those situations I have to take myself out of the story and build up the picture like I’m building flatpack furniture; ‘the instructions say that this was to the left, so where does that go?’. Then once I’ve built that model I’m off again, but that part is a different skill and experience from the rest of my reading, much more conscious and deliberate where the rest is just absorption. I’m not alone in this, if this Reddit thread is anything to go by.
Although people often default to an assumption that human comprehension and memory is all picture and text based, that isn’t universally the case. In my experience you can hold concepts in your mind without words or images, even if you might need words or images to communicate them to someone else.
In the course of looking for supporting articles for this answer I have discovered that I may, to a degree at least, have what is called ‘aphantasia’, as per this article in The Guardian newspaper. But note, the article says
“We know that children with aphantasia tend not to enjoy descriptive
texts, and this may well influence their reading comprehension,” says
neurologist Adam Zeman of the University of Exeter who, together with
his colleagues, gave the condition its name last year. “But there
isn’t any evidence directly linking it to learning disabilities yet.” (my emphasis)
I pretty much always skip over descriptive paragraphs, or lightly skim them, as they bore me to tears, but are generally not particularly essential to the plot. If I force myself to read them, I won't remember the detail of them later.
Lack of habitual visualising has never impacted on my ability to do the 3D questions in IQ tests (the which shape does this unfolded box make questions), or stopped me having a career as a landscape designer. I can design without it being a process of transcribing something I’ve pictured, and I can understand a plan someone else has drawn without it transporting me to a mental model of the site. If our brains can create structures the way this article describes it can be no surprise that there are more ways than just by pictures and words for our minds to hold ideas.
Although there are sites which will tell you that visualisation is essential to reading and comprehension, I know that if I had come across teachers who pushed this idea when I was in school it would have greatly deterred me from reading, and reading has been one of the great joys of my life.
I note that you have added some more to the question about fuzziness and lack or recall since I drafted this. I can't speak to that aspect other than to suggest that you have a think about whether other areas of life are affected the same way, and don't be shy of seeking a medical opinion if this is a change in your ability to read effectively, as there are conditions, stress, thyroid function or even a need for new glasses etc which can cause what sufferers often term 'mental fog'.
I'd still recommend that you not stress about lack of visualisation, unless of course that is something you have always previously been able to do.
