Hi everyone, so I reached out to Shelly Support team, and they were great. Here’s there answer:
“Thank you for the detailed explanation!
This is a known limitation at the moment. The input state in Detached mode is not currently exposed via Matter.
Our development team is already working on this, and support for exposing the input is planned for a future firmware update (possibly around version 1.8), but we do not have an official ETA yet.
At this time, there is unfortunately no workaround within SmartThings.
You can follow upcoming changes here:
https://shelly-api-docs.shelly.cloud/gen2/changelog/
We appreciate your feedback and apologize for the inconvenience.
Best Regards,
Shelly Support Team”
So good news! We can expect a new update to Shelly 1PM Mini Gen4 soon, to allow exposing the “input state” via matter in SmartThings.