I founded 2 photo startups (2004 and 2012). My second startup was focused on data portability and was open source. https://en.wikipedia.org/wiki/Trovebox
After failing to integrate the software into Western Digital's MyCloud NAS line of productions, I left and decided to try something different. I created a photo management tool that could feed into other photo programs. It's open source and available on github.
https://github.com/jmathai/elodie
I started off using it with Google Photos. Explained here, https://medium.com/swlh/my-automated-photo-workflow-using-go...
I've since switched to using it with Synology Photos.
8 years and counting.