iOS - Google Photos not syncing often enough

***"TL;DR":*** Does Google Photos app behave the same on iOS devices as on Android devices? It seems it makes backups much less frequently, and I couldn't find any data that supports that aside from some shady blog ([How Often Does Google Photos Backup On IPhone?](https://www.compsmag.com/blogs/how-often-does-google-photos-backup-on-iphone/)) . **Comment:** I can see individual storage for each family member (through Google One app or https://one.google.com) . The photos are being backed up occasionally, and after I see her storage not going up for a while, I ask her to open the app - then the storage immediately goes up. Or, if I open the app on her phone myself, I can see the backup status, and there are often dozens of photos/videos to be backed up. After it's finished, they show up in Google Photos. So the photos are being synchronized, but only at irregular intervals. *(Copied from my comment below to clarify)* **Premise:** I don't own an iPhone, but my niece recently (well, six months ago) got one. We use a family account for YouTube Premium and Google One for storage. All members have an Android except for the niece so it wouldn't make much sense to set up a paid iCloud account. **The problem:** We're used to Google Photos syncing instantly (on Android, when it's set up correctly). However, on her iPhone, it syncs once or twice a day at most. Sometimes, we have to remind her to open the "Google Photos" app for syncing when we notice no increase in Google One usage, as she's prone to losing/damaging her phones (and she loves taking photos and videos of everything, so if Google One usage remains the same - there's a problem). **The device:** It's an iPhone 11 Pro, using probably the latest iOS 16 version, as I do the upgrade every time I'm around. The last time was probably three days ago. However, the problem persisted ever since she got her iPhone. Google Photos seems to be always up-to-date, so I guess it downloads the app updates automatically. **What I've tried:** Of course, I've checked background apps. Google Photos is allowed on Wi-Fi and cell (unlimited plan). Battery savings is turned off. I've tried logging off and on. Yeah, we tried rebooting. However, it still only seems to run the sync at irregular intervals. ***"Irregular intervals":*** It's not so irregular, there seems to be a pattern. After she starts the app, it seems to work fine for the next few hours, if so. And then the updates become more and more irregular. After a while, it only updates once a day, or once in two days, and then we ask her to just open the app and close it.