Factory Reset in Catalina

Hi! I recently upgraded to Catalina (everything is running fine, no issues with the OS), but decided to do a clean wipe of the drive to start fresh. Normally, I'd just boot into recovery mode, erase "Macintosh HD", then reinstall the OS. But with the upgrade to Catalina, I now have "Macintosh HD" and "Macintosh HD - Data". I know the gist of the split drives - one is OS, one is my files/data. The question is, if I want to do a "factory reset" of the Mac (without having to create a bootable USB drive or do internet recovery or anything like that), which one do I delete (or do I delete both at the "container" level)? Do I even need to "reinstall the OS" like before, or will simply erasing the "Macintosh HD - Data" volume basically do the same thing as a factory reset?

Any help here is appreciated. Thanks!