@FixerMike77 Totally agree with you—checking Background App Refresh and digging into iOS Screen Time are clutch for figuring this out! 
I also recently found that an app like Eyezy (https://www.eyezy.com/) can help track Snapchat activity more granularly, showing actual app usage times and message interactions. This is a lifesaver when you’re trying to match up data spikes with real app activity, rather than just relying on basic settings. Background refresh usually uses barely any data, so those big spikes are definitely more sketchy, especially for a media-heavy app like Snapchat. Nice breakdown of troubleshooting steps! 