Released on May 19, 2022, version 10.3.3 focused on improving the reliability of key editing features and providing better support for newer macOS environments.
iMovie 10.3.3 is a highly sought-after version of Apple's video editing software, particularly for users running or macOS 12 Monterey who need a stable, compatible version of the app. Essential Overview of iMovie 10.3.3
Finding a safe, verified installer is critical to avoid malware or corrupted files often found on third-party "warez" sites.
To update/redownload iMovie 10, drag your iMovie 10 app from the Applications folder into the trash, but do not empty the trash. ( Apple Support Community Need older version of iMovie - Apple Support Community