I decided to give a try with my quick touchup in Krita 4.3 Alpha. I used Interpolation 2x, HSY’ Color and Saturation along with Guassian High Pass Adjustment Layer. A bit of G’MIC Pyramid Processing.
Since I can’t share .KRA file, here’s the layer setting.
- Guassian High Pass Adjustment Layer (Flat Light 90 Opacity)
- Original Layer at Color Blending Mode at 73 Opacity
- Original Interpolation 2x at 62 Opacity
- Original Saturation at 100 Opacity (This isn’t needed)
- G’MIC Processed via Pyramid Processing

EDIT:
My edit in Krita for any one that wanted it- edit.kra (4.0 MB)
Thanks, @patdavid! No longer need to mention how the layers are structured.