Apple does make great computers, phones, iPads, watches, etc. But one simple thing they could do, which wouldn't cost them anything but make their devices more useful, would be to give customers the option of picking any alternative cloud storage service (or even their own homelabs' storage solutions), instead of locking them to iCloud
Currently, iCloud gives one up to 5GB of free storage, but that's easily taken up by just an iPhone backup. If one has other devices so that the same data is available to all of Apple's devices signed onto that account, this turns out to be a bottleneck. For $0.99 a month, one can get that bumped up to 50GB. However, considering that iPhones now come w/ minimum 256GB and Macs w/ 1 or 2TB, one does have to pay monthly just to sync devices for which one has already handsomely paid Apple
Of course, it costs Apple money to procure such storage, which is why they need to charge customers in order to ensure that it's not a money sink. So my suggestion - exit that area completely (or retain it for customers more than happy to pay and don't wanna roll their own), so that people can sync their Apple devices if they want w/o an iCloud account. Another option, if Apple doesn't want to do that: enable Airdrop b/w Apple devices on the same account, so that I can offload my photos and entire WhatsApp chats from my iPhone to my Mac before wiping the former, w/o overwhelming my iCloud storage