Finally. The user experience of manually providing non-free firmware on a separate USB stick was horrible, even for a technical user. What Debian really expect

Finally. The user experience of manually providing non-free firmware on a separate USB stick was horrible, even for a technical user. What Debian really expects are DEB packages placed on the drive, not raw firmware files. Finding which package you need (the installer only tells you the raw firmware files, not the package containing them) and obtaining them is not straightforward - there is a web UI to browse packages and download files but navigating those requires existing domain knowledge of Debian and Linux in general. It is not a straightforward web form "want a package? enter package name and architecture and we'll give you the download link". I now know from memory which firmware packages my systems need and the requirements for the USB stick and how to navigate the web UIs to download packages, but the first time probably wasted an hour of my time searching around before piecing all the various (and sometimes contradictory) resources out there into a coherent solution that worked.