Downgrade from Catalina the easy way...

The easier method to downgrade from macOS Catalina to an older version of macOS (if your computer supports one). Uses Apple Internet Recovery. Does not require an external USB installer. This method does not give you a choice of which version comes down, so you may need to upgrade from that version to something in between, later. To do that, see the following: https://support.apple.com/en-us/HT211683. If you want full control, use the method that requires an external USB installer:    • Downgrade macOS Catalina to Mojave-from ba...