Your health and well-being are of paramount concern to us. What does 'of' mean here?
Solution 1:
"of paramount concern" is an prepositional adjectival phrase (an adjunct) and describes the [fundamental] nature of "Your health and well-being"[1].
"To us" is a free modifier (adverbial) that modifies the whole clause. The example can be written
"To us, your health and well-being are of paramount concern.
[1] Compare, as in my comment above, "The statue is of gold".