dedicated nas systems are pretty overpriced imo, often costing as much or more than the drives you put in them. much cheaper to build your own. depending on your needs, this can be as simple as a raspberry pi plus an external hard drive.
They are overpriced based on a system you can build yourself, but the target audience for a NAS is someone who doesn’t want to spend days googling guides when a hard drive craps the bed or the os glitches. When I think of how much my NAS was, what I have stored on it and how much I use it, it is probably the best value for money thing I own.
not that expensive, i got a secondhand synology ds218+ which is based on intel x86 architecture, it costs about 100 usd. campared to raspberry pi, it provides docker support. i deploys teslamate, homeassistant, and openwrt.