Qt embedded is actually pretty nifty. I converted an old GTK "bare metal" interface UI over to Qt once while keeping the "business" logic basically the same other than a couple of tweaks, it went pretty well. The app was pretty well partitioned between backend logic and GUI logic so it wasn't a bad experience at all. All in C++

How did you do licensing? That’s the killer for me on bare-metal.

I wasn't in on that, we had licensing, and I'm sure it was paid for. It was a medical devices company so they had pretty deep pockets.