Hi, I am not sure I understand exactly what you are trying to do, but yes APFS will be required for your MacOS system\boot drive in Catalina. Also, the old El Capitan Multibeast tools shouldn't be used with Catalina. If you read through this long thread (I'll save you of that!), I didn't always upgrade directly for each new version of the MacOS. At least twice, I chose to do a fresh new install of MacOS on a new SSD. That is what I would recommend for Catalina, a fresh install using the TonyMac guide for Catalina, and then in conjunction with this guide (the Catalina section) assuming your hardware is the same.
The following guide is a complete walkthrough for updating to or installing a fresh version of macOS Catalina. It requires no experience and all of the basic installation and post-installation tools are available on tonymacx86.com. Table of Contents Step 1: Download macOS Catalina Step 2...
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