I have been using an old PC as NAS and running docker containers (Immich, Nextcloud, paperless-ngx etc.). I got 5 3.5" HDD disks and a Nvme. Even on idle, I am consuming 50-60w. A friend of mine is selling a Qnap NAS which is a dedicated machine and probably consumes less power, although I don’t know if it’s worth it.
I use a 5600g on b450 ITX board and 4x 8GB Seagate drives and see about 35W idle and about 40W average. It used to be 45W because I was forced to use a GPU in addition to a 3600 to boot (even though its headless, just a bad bios setup that I can’t fix) and getting a CPU with graphics dropped my idle consumption quite a bit. I suspect the extra wattage for your machine is probably the bigger motherboard and the less efficient CPU.
It is possible to get the machine part down into single digits wattage and then about 5W a drive is the floor without spinning them down, so the minimum you could likely see with a much less powerful CPU is about 30-35W.