You have a 2012 MacBook Pro that runs perfectly. It cannot be updated beyond macOS Catalina. The App Store tells you, “iMovie requires macOS 11.0 or later.” You cannot download the current version. Your only hope is to find iMovie 10.3.3 via a DMG.
If you ever downloaded iMovie before on any Apple ID, log into the App Store on your old Mac. Go to your tab (not "Updates"). Search for iMovie. Sometimes Apple allows you to download the "last compatible version." If you see a cloud icon with a downward arrow, click it. You won't need a DMG at all. This is the only official way to get iMovie 10.3.3 in 2024/2025. imovie 1033 dmg verified
Some of the notable features of iMovie 10.3.3 include: You have a 2012 MacBook Pro that runs perfectly
: Once installed, open iMovie, click iMovie in the top menu bar, and select About iMovie to verify you are on version 10.3.3. Key Features of iMovie 10.3.3 Download imovie Version 10.3 - Apple Support Community Your only hope is to find iMovie 10