Can't upgrade to Catalina - only Catalina Beta is available
You don’t have to erase your current OS to make a new Catalina volume and install it cleanly.


How much space do I need to make a bootable Catalina volume on my Mojave Mac?


Once you get the version you want installed, you can migrate over the data or not as you please.

This saves you from having to erase first to test the install / get ready to erase the old OS that’s stuck in beta land.