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.
Old PCs often have that problem. My “NAS” is more a full on proxmox server with an AM5 CPU, 64GB ECC and yet it halved my power consumption compared to its predecessors.