There is no trustworthy "free fixed exclusive" steam_api64.dll . Treat any such download as highly suspect. For academic or informational writing, focus on how malware disguises itself as game cracks and DLL fixes.
Downloading standalone DLL files from third-party websites exposes you to severe risks:
The steam_api64r.dll file is a dynamic link library (DLL) component utilized by various video games tied to the Steam ecosystem.