Recommendations for a Photo Management Tool?

Like probably most of us, I have accumulated gigabytes of digital photos over the last 20-odd years. Over the years I have occasionally tried to organise them into folders, either by subject matter, or by timestamps, or both -- but each time I have given up, and now I have a mess of folders, some photos being duplicated and scattered without any real order.

Can someone recommend a good software tool to automate the task of photo management? Ideally it would be able to dig through multiple levels of nested directories, recognise photographs and identify duplicates, and then automatically group them at the very list based on years/months, and possibly on geolocation (assuming it is stored in the metadata). A next level would be the ability to somehow label and/or group the photos by recognising certain items in them, although that would just be a nice extra.

A nice UI is a welcome bonus, but by no means a requirement. I would be happy if it worked on Linux, but Windows would also be fine, as long as the end result is a directory structure containing photos.

Any ideas?