iMovie App Alternative

Take a look at Davinci Resolve.

https://www.blackmagicdesign.com/products/davinciresolve

However, is there any reason why Monterey won’t “take” iMovie? What are you doing to obtain it, and what happened when you tried?

— Rich

Try this....

Drag your current version of iMovie to the trash but do not empty the trash just yet.

Open the App Store and click on your name at bottom left.

This should take you to your Purchased page which should list the apps associated with your Apple ID.

You should see iMovie listed on this purchased page and should be able to download a compatible version for the OS that you are running.

As Rich hints, you should be able to download iMovie.

A word of warning about Davinci Resolve . . . it is a complete professional app, equal to or better than Final Cut Pro and as such it has quite a steep learning curve.

A simpler editing app is OpenShot.

https://www.openshot.org/

There are countless beginner tutorials for both apps on YouTube.