A desktop would need more connectivity than the Neo has. Figure on USB (2.0 at least) for a keyboard, mouse, and camera. Plus, some way to connect one or more monitors (HDMI, most likely) external storage (would need at least USB 3.0), ethernet (ideally 10Gbps or faster), and a different power supply.
Worst case - say this has the same I/O as the Neo & lacks an internal power supply - except the Neo Mini doesn't have a built-in display, so probably both of the ports could offer video.
1 x USB C 3.0 + charge + video
1 x USB C 2.0 + charge + video
Best solution, get a USB-C display so a single cable will provide power
and give you some downstream USB-2 ports. Better still if you can plug this into the USB 2 port to leave your USB-3 port open.
Second best solution - use a HDMI display via the Apple USB-C to AV multiport adapter which gives you a HDMI port, replicates a USB-C charge port and gives you a USB 2 port into the bargain. Or, any of the many, many multiport adapters or USB-C hubs on the market.
You've still got the second USB-C port for external storage etc. Bluetooth for keyboard/mouse *plus* both the above options give you an extra USB-2 port or two. Velcro it to the back of a cheap USB-C display and you've got an ersatz iMac...
That's assuming that not having the internal keyboard, trackpad and webcam doesn't free up enough I/O for an extra USB port.
Would I put up with a Mac with such limited I/O? Heck, no - but it would be a working system if they could offer it for $200-$300 or so. Being worse than the M4 Mac Mini is part of the product brief.
Not saying it's remotely likely - as I've posted before, the Mini is already niche compared to the MacBook range - people prefer laptops these days, Apple wouldn't get the huge volumes of sales to justify a really low price
and the smaller sales across the Mini range (c.f. the MB Air) would be more vulnerable to cannibalisation.