Based on my (very high-level understanding) Windows 10 IoT core requires UWP apps. And it looks like it's in tier 3 support. However, I may be misread this either on Windows 10 IoT side or not fully understand the Rust side.
Is IoT Core still a thing? I thought it was dead. MS released it for the Raspberry Pi some years ago. It never got support or updates. I believe it does not run on new Pi models. What platform do you want to run it on?
It's running on a point-of-sale device. Right now, I am early in the feasibility investigation. (BTW. There is a good chance that they run Win10 IoT Enterprise in there, I still need to figure out this bit of info).
Yeah, IoT Core supported Rasberry Pi 2 and 3. However, it doesn't support 4.
I have no idea whether it's a thing or not on a bigger scale. On the one hand, I saw a bunch of "flags" that it's not widely adopted. On the other hand, Microsoft released Windows 11 IoT, which implies that they still push it forward.
As bjorn3 says you should be able to compile non-gui Rust applications for IoT Core. The only caveat is that IoT Core has a reduced Windows API. The stdlib should be fine though third party crates may or may not.
If you do want a GUI then the usual way is to wrap a Rust cdylib in a UWP C# application. The C# application takes care of the UI and forwards actions/events to the cdylib. This design also makes packaging easier because it has good first party support.