I too was looking for a replacement for Lightroom Classic. I was hoping this could be it. I downloaded it and quickly found that it is not it.
- Photomater's photo library is the Apple Photos library
- Files are copied into the Apple Photos library when importing, even when Photos.app has the preference set not to
- Edits are not saved to the dng. (There is a preference to save a sidecar file when editing, but I couldn't find the sidecar. Could be a bug.)
I think that if they had just not used the Apple Photos library for their library, and had their own library browser, I probably would have bought it. The app performed really well and the experience was nice for simple photo edits. Their B&W editor was nice, and seemed to maintain brightness while adjusting individual color channels.
I'm still holding onto my LR6 perpetual license as tight as I can, even with all of the broken features, waiting for something that isn't a subscription that can function as a photo library and editor.