Raspberry Pi won't do unfortunately, unless you run up to 4 lightweight containers.
Does the author know how much compute power a Raspberry Pi 5 has? If the software that just hosts personal data can't run in Raspberry Pi 5, that should be a terrible software. For most people and their families, a RPi5 is enough to host anything that they would ever need.
For most stuff the pi4 is also enough. Jellyfin (no transcoding) works fine on mine. It takes a bit to generate the chapter images and the timeline peek images when ingesting a new movie, but I've never had any issues with playback.
was this article even written when the pi5 was out? The pi4 was out, and pretty good for quite a while, but really expensive in the last four years. The pi 5 is up there, but the price almost makes sense, so.
you can do quite a bit on these machines, but they are inherently limited, running a proper nas is going to be rather goofy, and probably just justifies getting proper hardware at the end of the day.