Even if the file "works," it cannot provide the full Premium experience because many features are controlled on Spotify's servers, not within the app itself.
Files distributed as .rar archives on unofficial websites are a primary vector for malware. Spotify Premium.rar
A file named typically claims to contain a "cracked" or modified version of the Spotify application designed to unlock paid features for free. However, downloading and using such files carries significant security risks and functional limitations. Security Risks and Warnings Even if the file "works," it cannot provide
: Security researchers, such as Bitdefender Labs, have identified modified music apps as a major source of mobile and desktop malware. - SoundGuys
Instead of risking a .rar file, consider official ways to reduce costs or try Premium: Spotify Free vs Premium: Is it worth it? - SoundGuys