I use Photoscape. I'm on a Mac. It is easy to use, but not at all comprehensive.
I used Photoshop for years. Photoscape does not compare, but it's "quick and dirty" as my Dad would put it. It's effective for what I primarily need it for - real estate photos and writing words or arrows on photos. And I can make most pictures I want to keep or share look better, too. But not art quality by any means.
I just watched the video in the post about Darktable - wow, that looks cool. That program is much more like Photoshop.
Be joyful, though you have considered all the facts. ~Wendell Berry
Essentially there are three main processes involved in digital imaging after the image has been captured.
1. DAM (digital asset management) relates to cataloguing the images using the associated metadata - in other words a database. A good DAM should be able to locate images very quickly based on various criteria. This becomes very important as one's image collection grows. Lightroom has an excellent database facility.
2. Raw conversion and non-destructive image editing (as raw files can not be directly edited). Lightroom has an excellent raw converter and non-destructive image editor which is fully integrated with its database. Other apps which do raw conversion and non-destructive image editing include Photolab3 by DxO mentioned above which is very good and reasonably priced and Capture One which is reputedly very good but also very expensive.
3. Pixel-based photo editors such as Photoshop allow modification of the actual pixels in a file and are the go to tool for detailed retouching (including removing dust spots) and layer-based image editing. Affinity Photo is another pixel-based image editor.