For me the katastematic "pleasure at rest" is a mental sense of satisfaction and gratitude, a quiet feeling of joy...when everything is fullfilled.
See the difficulty there is that if you can "feel" the sensation of pleasure -- which I think is doubly clear when you refer to it as joy, then by definition according to the scholars what you are feeling is not katastematic pleasure - it is kinetic simply because you do in fact feel and enjoy it.
Once again I want to be especially clear: I am not criticizing yours or anyone else's descriptions of what you feel. What I am doing is pointing out that when you dive deep into the technical terms that they were using in ancient Greeks, there is a lot of specificity that we as "normal people" who haven't devoted our lives to studying ancient Greek and Greek philosophy don't have any way of knowing about.
In fact as I write this comment I think what we're talking about here is exactly what a large number of commentators are doing and have done to us. We all can feel at times what it means to "rest" and to have a "good attitude" and a "positive outlook" and similar emotions feelings. We know that those are important to us, and so when we read (from the commentators!!!) that Epicurus was really interested in "resting" pleasures, we presume "Oh that makes sense and I totally agree!" and we end up endorsing the "kinetic / katastematic distinction" as if it were a really important part of Epicurean philosophy.
To the contrary, I think Nikolsky, Gosling & Taylor, Wenham, and others (I'll include dewitt here) have totally demolished that argument and upended the academic viewpoint. They have done so not by showing that such pleasures don't exist - they clearly do! But rather the academic viewpoint has never been consistent with or perceptive in understanding what Epicurus taught. You can't follow the full argument without the information that Nikolsky provides, which is that this darned katastematic-kinetic distinction is an essentially STOIC method of categorization, and that it likely appears in Diogenes Laertius only because by 300 AD (when DL wrote) and even by 50 BC (when Cicero was trying to defeat Epicureans with word games) it had become common practice among philosophers to split up types of pleasures using those terms. DL was going through chapter after chapter of Greek philosophers attempting to explain their positions in terms that people in 300AD would expect to see, and in 300 AD most people interested in philosophy (not necessarily including Epicureans of the day) expected to hear about katastematic pleasure.
OK - again - these aren't my arguments, these are the arguments of people a lot smarter than me (Gosling, Taylor, Nikolsky, etc.)
But I will repeat too that I think Wenham points out a real key to the situation. If you always keep in mind that nothing trumps PD2, and that all good and evil comes to us through sensation, and without sensation we're dead, and that nothing that doesn't produce sensation is of any concern to us, then you will burn in your mind that "pleasure" (which we all seem to agree is the ultimate goal) must come to us through sensation - through experience. And is apparently universal among the literati that the definition of katastematic pleasure EXCLUDES pleasure that can be sensed. I leave it to you to unwind what that means as to "katastematic pleasure" as the ancient Greeks defined it, but I suggest to everyone that Epicurus was interested in pleasure that can be felt. Pleasure that can't be felt - no matter what term is applied to it, not only cannot therefore be the highest good, as so many allege, but I would allege in turn that if it can't be felt it is of no more concern to us than death itself.
Which makes it prime territory for the Stoics and other logicians, who apparently where the ones obsessing over the term.