Used the AI object mask on the bird and branch, works well. Inverted the mask to use Blurs on the background.There was a faint edge/halo around the bill and belly area… Adjusted feathering as per guidelines and changed the blend mode for the background to “harmonic mean”. It “removed” the halos and edge. Applied Tone and Contrast Equalizer modules and slight color calibration.
Edit done in Darktable running Zorin OS 18.1 (Linux)
To me, it still looks like there is some halos around the bird, especially above the bill and the ruffled feathers near the tail. The background also looks like it has quite a few artifacts (blue splotches against gray?)
Geometric Mean is like Average, but it leans towards the lower of the two values.
Harmonic Mean is like Geometric Mean, but it leans a bit further towards the lower value.