Same here. DigiKam and darktable.
Getting color balance with raw in darktable took quite a while for us. It was helped by using a Color Checker Passport in a few shooting conditions to use for reference and calibration. Once we got past that darktable has been great.

Digikam was my replacement for photo management and tagging. And darktable for editing. You can launch darktable from the Digikam catalogue, so it's pretty smooth.
It took me a while to get used to darktable, especially the masking, but I genuinely prefer it to lightroom now.
You can also use other editing apps, like Gwenview, etc for quick and dirty edits. The only thing I've had no luck with are things like Topaz and DxO. They won't run on Linux and don't really have equivalents.
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