Ok, after doing some photoshoots, I tried to use RawTherapee, but however it doesn’t support .heif file, so I went with DarkTable, and I find it incredibly easy to get vibrant pictures. I actually like going just the bare adjustment.
I usually go with exposure, turn it on the maximum because the preview is just so dark, and use Color Balance RGB, and that’s pretty it. Occasionally, I look into other things if need to be.
HEIF is a container format for photographic images, not a RAW format. It supports different encodings and different types of data like individual images, thumbnails, image sequences … and more.
The fact that the imported HEIF (which, as mentioned, is in no way the same as raw) is very dark could also be because it is encoded w/ a HDR PQ transfer curve, which has a very large range (1.0 is absolute 10000 nits). This is typically the case w/ modern Canon camera output I think…