Let me know how I can help you ! Any way of getting GarageBand on macOS Catalina (10.15.7)?

If you have very old audio plugins (VST/AU) from 5-10 years ago that are 32-bit, GarageBand on Catalina will not see them. Unlike Mojave (10.14), there is no native support. You will need third-party software like "32Lives" to bridge them, which can be buggy.

If you have ever downloaded GarageBand in the past using your Apple ID, the App Store allows you to download the last compatible version for Catalina. Open the on your Mac.

Are you getting a specific when trying to install? Share public link

You will find many websites offering direct downloads of "GarageBand 10.3.5 for Catalina." However, many users warn that these sites often contain malware or viruses. The safest way to get the app is through the official App Store using the methods above. If a source is not Apple's App Store or your own Time Machine, the risk of compromising your system is high.

to the Mac App Store on a newer Mac (running macOS Big Sur or later) using your Apple ID.

: Scroll through your "Purchased" list until you find GarageBand. : Click the Cloud/Download Confirm Older Version

If you download a DMG from the web, you may need to go to System Preferences > Security & Privacy to allow the app to open.