OK, I think I have a working solution to this for now, using two apps.
1 - XnView - the bulk rename works extremely well. Using a template very easy to change files ending in (1) to just 001. This solved one of my main issues, as I kept seeing photos out of place in sequence and thinking they were duplicates. XnView does a good job of finding duplicates as well, even though the interface for choosing and deleting one of each is a bit wonky.
2 - Darktable - the interface isn’t quite as intuitive as I’d like, but a small investment of time in reading some manual pages pays off. In lighttable mode I can handle the metadata - attach or detach tags, add titles and descriptions in bulk. Once in the darkroom mode, the space bar advances one photo, backspace goes back one. To select an image to be removed you use the ‘r’ key. I can easily apply base curve presets manually or apply them in bulk during import. That right there is the main feature I’ve been trying to find and use over the last month.
Having said that, the ability to export to Flickr seems to be broken. I’ve found bug reports 18 months old on this. Guess I need to try to duplicate all of these same things with RawTherapee…
Using these two apps, in this order, should give me the bulk