Do not convert these to FLAC. Since the source is likely a low-bitrate MP3 from 2001, converting to a "lossless" format will only waste space without improving quality.
If you are adding these files to a modern library (Spotify Local Files, Apple Music, etc.): 2001. Denisa - Gelozie.rar
Look for early hits like "Gelozie," "Dacă pozele ar vorbi," or collaborations with Florin Pește. Do not convert these to FLAC