Final Cut Pro 10.5.4 (MAS) is a July 2021 update for macOS 10.15.6 or later, designed to improve stability and performance for H.264/HEVC media on Intel and Apple silicon Macs. The update requires approximately 4-7 GB of free space and is installed by mounting the DMG file and running the included package installer. For official, safe installation, it is recommended to download directly from the Apple Support website
To understand 10.5.4, it’s helpful to look at what it builds upon from the milestone 10.5 release: Final-Cut-Pro-10.5.4-MAS.dmg
If you'd like to tailor this for a , tell me: Should I focus more on technical specs (GPU/RAM)? Final Cut Pro 10