Well, this is the app that answers that. Everything is seamless, you don't configure anything. You simply start the app on the Mac Mini, import the photo folder, and let it run in the background. In the kitchen, you simply take your iPhone or iPad, open the app and voila, all photos from all libraries show up, organized by date, place, album, people, event. You want to see photos from Prague? You simply check Prague from the filter sidebar. You want those from 2008? You check 2008. Done.
This is not an AI search-based photo library. You cannot even search. Everything you can search for is laid out in the sidebar. You don't need to remember where you have been in 2008. You check 2008 - you see all locations, all albums, everything from that year. You want to see how many trips you had to Vienna? You check Vienna. It's kind of old school this way, but I find it much mentally sane to see a list of filters with things you have done and places you have been and dates you took photos in, rather than an empty search input open to guesses and missed attempts.
This is also not a replacement for your Apple Photos app, or a photo editor app. This is not a photo editor. It's simply a better way to browse historical photos, in a home network, without thinking about it.