Is there a linguistic term for the phrases, which describe a noun, with subjective value (below)

Each one is an example of a type of a metaphor defined by the Cambridge online dictionary as

an expression, often found in literature, that describes a person or object by referring to something that is considered to have similar characteristics to that person or object:

Metaphors often, but not always, have this "A (something) of (something else)" structure but can have other structures such as "(something) is a (something else)". An example of that type of metaphor from the linked dictionary entry is "The city is a jungle". That's obviously not literally true, cities and jungles are two different things, but the metaphor presents the comparison as though it were a fact.

This is as opposed to a simile which is defined by the same dictionary as

(the use of) an expression comparing one thing with another, always including the words "as" or "like":

For instance if your second example had been "A man like a big bear" rather than "A big bear of a man" that would have been a simile since the comparison is made explicit by the use of the word "like" whereas in a metaphor the comparison is concealed by the metaphor looking like a statement of literal fact.