Run it on a machine with macOS 10.14 (Mojave) or earlier.
If you don't want to risk malware or legal grey areas, consider these modern alternatives that replicate the FCP7 experience. final cut pro 7 dmg
: Unlike the "Magnetic Timeline" of modern FCP, version 7 used a traditional track-based system that many editors still prefer. Run it on a machine with macOS 10