I can’t imagine what would make someone believe that storing hundreds of thousands of dollars worth of Bitcoin in a mobile phone wallet was a good idea. Sparrow is a reputable name that people trust, but at least they should have checked on their website to see if they actually have a mobile application.
User error aside, Apple has been extremely negligent in allowing fake crypto wallet apps in their store. There has also been stories about fake Electrum wallets that got people drained of their funds. Currently, I can find a fake Wasabi Wallet app in the Apple App Store and also something called Safe3, that is probably trying to trick users into believing they are related to Trezor. One of that wallet’s reviews is from a user who claims their funds were stolen.
All this fake wallets and apps that could even be downloaded from Apple store or play store makes me doubt the efficacy of using a hardware wallet that is downloaded and installed on a device. Perhaps they paid some amount of money to market these fake sites on the apple or play store and these companies don't do due diligence test to know the originality of the source before allowing users download it.
If there's a way for Bitcoin users to use cold wallets hardware that's airgapped, I think it would be a better option than the wallets that can be downloaded from any store because hackers are also developers than build sites to decieve the unsuspecting and those who aren't as much tech savvy and have such huge holdings in one place always fall victims no matter how careful they are.
I would advice anyone including myself to never store my Bitcoin investment and holdings in one wallet as a way to not lose all I have accumulated overtime due to such kind of hacks and fake wallet apps.