(Google Sheets) How to find column 1 and row 1 values for a matrix of occurrences in which both are present in data

( edit: Rough idea of what I'm trying to do: https://docs.google.com/spreadsheets/d/12rIUiuE-TSB0E3XRSnQ0YU9BCpuTsHfrUZXgCvxOE44/edit#gid=2100307022 )

I feel like this should have a really simple solution, but I can't work it out...

Basically, I am analysing a table of tagging data in which more than one tag can be applied to the same record. I am interested in seeing which tags occur together most frequently, so I have created a matrix as such, showing tags in the first column and row, and their co-occurrence in the count matrix below:

Simplified version of matrix - the version I'm using has 60 X and 60 Y items

Below it, I've pulled the highest numbers from the matrix (i.e. where the X and Y values appear the most - 5 in the above case), but am really struggling to work out how to simply create a function that will find the column and row header values for each.

Essentially, I ultimately want e.g. in this case:

5: A & D (where 5 = number of times A and D occur together) (plus any others where the number of co-occurrences is greater than X)

It's highly possible that I got stuck in the woods with this one and there's an easier way to do this, or that I'm just overlooking a simple formula I could use, but at the moment I can't think of a code to create for this that wouldn't be incredibly long or time-consuming.

I've thought of ways to do it with MATCH and INDEX, but I'm not particularly strong with these functions tbh and can't work out how to use them in a 2-D array like this. I've also thought about using combinations of FILTER, FLATTEN and different LOOKUPS, but likewise can't work it out.

Any help would be much appreciated.

Here's one approach you may test out:

=let(Σ,sort(unique(reduce(,O2:X11,lambda(a,c,vstack(a,{c,torow(sort(tocol({index(N1:N11,row(c)),index(A1:X1,column(c))}),1,))})))),1,),
       filter(Σ,index(Σ,,1)>=3,--index(Σ,,1)))

• X value is taken as >=3 for test purposes