"保有不动产权者" can be translated into English as "holders of real property rights" or "owners of immovable property rights".
"Holders of real property rights" emphasizes the legal possession or ownership of real estate (real property), which includes land and buildings permanently attached to it.
"Owners of immovable property rights" is also a valid translation, as "immovable property" is a legal term referring to land and things permanently attached to the land, aligning closely with the concept of 不动产 (bú dòng chǎn) in Chinese.
Both expressions convey the idea of individuals or entities who legally possess or own real estate rights.