I defined “knowledge” as being a type of information, specifically useful ones. That means knowledge is a subset of information. Many concepts are defined like this. For example: a bachelor is man who has never married. Is a bachelor a man? Yes. Does that mean the definition is circular? No. Can you sometimes substitute “man” for “bachelor”? Yes. Can you always? No. Are they synonymous? No.
I guess some synonyms are subset and superset? In that case the differentiation must be minimal. Useful information is very different from useless information and you can also break information into false and true information. So we can’t equate knowledge with information.
I didn’t know that. Why do you know that? You can have abstract purposes like “understand Chinese history.” The historians who figured that out adapted that information for the purpose of understanding Chinese history. It is knowledge because it was information adapted by the historians.
An example: how many grains of sand there are in a beach.
Is it a problem to apply “useless” to your understanding of information? If so why? Are you asking for a definition of “information”?