Colin, it sounds like you have thought very hard about this and are in a similar place to me. I agree that Photos for Mac seems to be the best option for viewing and quick glance of images. I hate the file structure it uses and agree that keeping photos separated by date is best practice. It’s much easier to move libraries, future proof, and reduce reliance on a particular app.
My question is how do you go about editing your photos? You said you use photoshop, do you shoot raw and use camera raw? I’m currently running an older version of MacOS (I think 10.14) and when I tried using the keep files in original location structure the external editor does not link to the original file. So instead I get the thumbnail image opened into Capture One (not my favorite to have to import every time to edit a photo). I may look into other apps as an external editor. Do you have any issues with using an external editor or do you just open the original in the folder and then chose your app of choice to edit?
I keep looking for a better DAM/photo library manager but haven’t found a better option either.