Good morning,I've found that using the latest OCLP to download the installer (it puts it in ~/Applications) works best for me. I don't run the second part (flashing a bootable installer USB), it's not necessary unless you need to clean install on, for example another volume- or machine, or squeeky-clean install on your main drive. After downloading I just double click on it in ~/Applications and install Sequoia over top on the current boot drive.
When you install as described, how does OCLP then interact to ensure other necessary routines, such as KDK, are downloaded?