The search function in Google photos is really the main factor why I'd want to continue using it. I wish there were a photo search index I could run on my own hdd.
Curious what indexing features you find most useful. For me the killer feature was how ocr rendered a lot of photos searchable by the text contained in the photo. But also cool how you can search “mountains” and see all your photos related to that.
I like being able to search by location and peoples names. Similar features are present in my phone's gallery (Samsung) but it obviously works only on the photos in device. Google photos searches all the photos taken by my wife and I over the last half a decade.
Apple's Photos app has a decent search-by-contents feature. Even better, the analysis is all on-device -- it isn't server-side, and doesn't rely on you uploading your photos to iCloud.
Samsung gallery also has same features but it works only on the photos stored on the phone. A big plus with Google photos is that it operates on my entire collection even when I clean pics up from my phone.
If you use Windows the built-in Photos app has pretty good indexing.