Currently downloading my Google Photos data with their Takeout tool, and will make dupeGuru to good use (sorting ~ 20 Gb): https://dupeguru.voltaicideas.net/
dupeGuru
dupeGuru is a cross-platform (Linux, OS X, Windows) GUI tool to find duplicate files in a system. It’s written mostly in Python 3 and has the peculiarity of using multiple GUI toolkits, all using the same core Python code. On OS X, the UI layer is written in Objective-C and uses Cocoa. On Linux & Windows, it’s written in Python and uses Qt5.

