[pimpim]

I got a bit more practice printing photos... Just sliding the gamma will quickly make the whole photo washed out. So that only helps for tiny corrections.

What probably will help is tweaking the actual curve a bit, but I guess if I'm going there I might as well start photographing in RAW altogether

[pimpim]

Addition to the Canon Selphy topic:

It is possible to push the quality a bit by loading icc profiles for it into your operating system:
for example: https://www.objektiv-guide.de/icc-profil-canon-selphy/ (there are probably more profiles to be found on the internet, no official Canon ones though)

I didn't do a scientific test to compare the results but the first prints with the new profile looked like they had a pretty nice color rendition.