Automate packages install from list in portable miktex installation

Question

I am trying to update an automated script for the creation of a portable miktex installation with specific packages. I can't get it to install the packages.

I have a file packes.txt that contains all the packages that I need (1 package per line) and the current installation process:

1. Download miktex installer and rename it to miktex-portable.exe (as per instructions here: https://miktex.org/howto/portable-edition)

2. Install the portable version to the location I want it (for simplicity I call the folder mikport here):

   miktex-portable.exe --portable=mikport --package-set=basic --unattended

3. Install the list of packages (this step does not seem to do what I want)

   mikport\miktex.exe packages install --package-id-file packages.txt

   as per https://docs.miktex.org/manual/miktex-packages.html

4. Run mikport\miktex.exe packages update

5. Run a test build with pdflatex

The test fails because of missing packages that are supposed to have been installed in step 3. I may have misunderstood the command, I assumed it to be a replacement for the deprecated mpm require=@packages.txt. Is there a way to automate this (e.g. without using the miktex console)?