If your daily digital life relies on Google Services, once you become an iPhone owner this may not change. I was a long-term Android user before I changed to the Apple ecosystem.
Even though Apple is offering their equivalent of what Google offers on Android, I never found a better alternative for storing pictures than Google Photos.
Google Photos for most of the typical users is unreplaceable due to the Storage Saver option. Thanks to that we can store all our photos and do not pay too much for the storage. At some point we will need to pay Google to store them, however as they are compressed, they consume less space than storing them in full resolution in, for example, Apple Photo Library.
The first thing that I do when setting up my iPhone is to download the Google Photos app from the App Store. This is what I recommend to my friends who switch from Android to iPhone, however, there is one thing that needs to be remembered.