Many musicians prefer staying on Catalina 10.15.7 because it was the last macOS to support certain 32-bit bridges and specific hardware drivers, while still being modern enough to run . This version of GarageBand includes:
If your download stalls while grabbing the extra instruments or loops: Garageband For Catalina 10.15.7 -FREE- Download
When a pop-up appears asking if you want to "Download an older version," click Many musicians prefer staying on Catalina 10
Access to thousands of loops, instruments, and "Drummers." Garageband For Catalina 10.15.7 -FREE- Download
For 99% of Catalina users, GarageBand wins by a landslide—especially because it’s free and fully integrated with macOS Core Audio.
Once the download begins, you can cancel it and of your Apple ID on that Mac.