In my reader, I've only seen a smattering of IOS apps mentioned as trackers/malware vs android but I wonder if that's because of Apple's higher-walled garden for their apps. I feel like IOS has fewer problems but they have fewer apps available, too.
Anyone even half-aware of security and tracking should keep apps to an absolute minimum. They should also explore options their phone may have that force stop apps running in background. I've posted before that I depend on Samsung's Ultra Power-Saver feature to force stop sneaky apps.