The workflow to get a deep-copy of a modifier is complicated and confusing.
If I use object >> Transfer/Link >> Copy Modifiers, I get a linked (not copied) modifier that I can then make a single user copy and have a complete, deep copy. So it is not a copy operation as implied by the button label (copy modifier)
If I use ctl-C Copy Modifiers (or copy selected modifiers), I get a virgin modifier, with none of the (desired) detailed properties set. I don’t see where this is even marginally useful.
There should be the ability to copy shallow and copy deep (sure: and link), and be distinguishable.