Apple does not officially offer older versions to first-time "buyers" on older OS versions. If you search the App Store directly, it will simply say your Mac is incompatible. You can bypass this with a workaround:
“GarageBand.app” can’t be opened because Apple cannot check it for malicious software. This software needs to be updated. Contact the developer for more information. garageband catalina 10.15 7 download
A common issue on Catalina 10.15.7: GarageBand installs, but when you try to download the additional , it fails or hangs. Apple does not officially offer older versions to
Navigate to Applications > App Store or use Spotlight ( Cmd + Space ). garageband catalina 10.15 7 download
Features like Flex Time to quickly change the timing of audio recordings and Groove Track to align the rhythm of all tracks with one click.