It wont work on s25 ultra even if you download an app for it because there is no hardware in your phone to support that. This is my take. But you can check with Samsung customer support if you need more info on that.

Oh nice. Let me check that.

If you own samsung products like ac or tv, you can use smartthings app to control your devices. But this app is only for samsung devices.

I checked in google and s25 ultra doesnt support ir blaster neither it has that hardware for future support.

Your smartphone should support it at hardware level. It is not something that can be provided as a software feature. Which smartphone do you have?