I agree, especially about the integrated USP and peripherals.
In my case, I currently use a Macbook Air M1 (my personal one which I currently don't need as a laptop). Absolute overkill and in some aspects annoying - only two USB-C ports for example - but it was available and it's fanless and doesn't need much power.
What storage enclosure (Thunderbolt?) and network filesystem do you use?
When there's a MacOS security update and the Macbook reboots, do NAS functions work before a local user has logged in?
Just a random powered USB-C Hub with a few external drives on one port and a Thunderbolt SSD I had from an old project on the other. For now, I just use the SMB server built into MacOS because I've not gotten around to installing Asahi on it.
I think I turned auto update off on this machine but if it reboots, you would have to login first. Doesn't bother me, though. I don't have any uptime requirements.
You can fully control when macOS does updates of any kind with a couple of UI toggles.
Any launch daemon service will load and/or start at boot, only user-domain services require a login (like the Dock or menu bar would)