Hello,

Here is my method, which is basically very similar.

Requirements:

- the custom ROM is available. It is best to rename it to a simple name, e.g. "rom.zip"
- Download Nikgapps Full...rename to "gapps.zip"
- Pixel Experience Recovery must be installed

Basics:

- If you want root, patch the "boot.img" via Magisk (24.3) in advance. Save the patched "boot.img" on the PC.
- you can customize the installation packages for Nikgapps using the "nikgapps.config" (located in the "afzc\" folder in the "gapps.zip". That's why the Full Package, because you can configure it as you like.
To do this, set the value for "use_zip_config" to "1" in "nikgapps.config" --> "use_zip_config=1". Now the packages in the config can be selected or deselected with "0" or "1". Attention : The Velvet package is also required for a working Assistant.

Steps:

- boot into PE Recovery, wipe everything under "Factory reset", i.e. system, data and cache (note: this point only applies to a new installation).
- then "Apply update" --> "Apply from ADB"
- in ADB "adb sideload rom.zip"
- reboot into PE Recovery
- in ADB "adb sideload gapps.zip"
- "Factory reset" --> "format data/factory reset" (again)
If root is desired:
- reboot into the bootloader (fastboot)
- here then "fastboot flash boot boot.img"

That's it! The phone should now be directly encrypted. No DFE is needed anymore.

Install future updates as follows:

- in ADB "adb sideload "rom_update.zip"
- see if the phone boots into the system
- if not --> "adb sideload gapps.zip"
- boot into the system
If root:
- Patch "boot.img" from "rom_update.zip" (in advance...BEFORE the update, save on the PC)
- flash via using "fastboot flash boot boot_update.img".

I hope the explanation helps one or the other. In any case, it works very well for me!