First Pi 4 to be used as a desktop computer.
I have used the option from a 64GB SD with NOOBS to install Raspberry Pi Buster.
I noted that during install there is an option to create a Data partition which I did on both, but have no idea what it can be used for, subsequently deleted.
There was also a warning that installing Buster would wipe the SD, but I had a problem with the installation and decided to do a new install by holding down the Shift key when prompted by the flash screen with the raspberry. It seems I still had the choices I initially had so it doesn't look like the SD is actually wiped. It may be that the warnings are generic and would apply to anyone installing Buster on a clean SD.
Second Pi 4 to be used as a www server.
Using the 128GB SD with NOOBS I have installed the Rasp Pi Buster and data partition
See https://www.raspberrypi.org/help/noobs%20setup/ for instructions on a manual download rather than buying pre-installed on an SD card.