The openHAB main UI has a build in option to display a parameter as QR code. This can’t be directly used for displaying the QR code as channel. But means it should be possible to create a widget using the already present QR code library. The parameter-qrcode can be found here: openhab-webui/parameter-qrcode.vue at 3.3.0.M2 · openhab/openhab-webui · GitHub
