Faded colors of old slides - how to improve?

Hi,
I am still working on digitizing my slide-collection by taking pictures of the slides within the slide projector. In the meanwhile I got a series of slides which colors are faded and I try to improve it by processing:
First I convert the raw by rawtherapee, than I am using standard procedures of digikam. The results are better but can it be improved further? Some examples.
Is there a standard routine for improving faded slides/pictures?
Best regards,
Markus

Not sure how to answer your question, but I liked very much the colors from the second shot in the row (the equalise one)

You’re taking a photo of the projected slide?

There is some information in this thread on how to restore slides.

For what it’ s worth, I believe the original picture corresponding to the slide you show was actually a little overexposed to begin with (the sky has zero detail- could also be heavy overcast weather), which means you can only get so much back in restoration from the slide. I’ve struggled with this too, see e.g. here.
Your second attempt is already quite nice!

No, I take the photo from the slide within the projector, using a macro. The projector is used for illumination and transportation of the slide.