Newer iMovie updates often include features optimized for Apple Silicon (M1/M2/M3 chips). On older Intel-based Macs (2012-2017 models), these updates can cause slowdowns and rendering glitches. iMovie 10.2.5 is lighter and better optimized for older processors and integrated graphics.
Because this is an old version, it is not available on the official Mac App Store (only the latest version is there).
Possible sources (use with caution): imovie 1025 dmg
To successfully install and run the iMovie 10.2.5 DMG, the target system must meet specific criteria: Newer iMovie updates often include features optimized for