The user is the biggest vulnerability and not the OS, regardless of hardening. You won't get hacked if you don't do anything wrong on desktops either. Mobile wallets lose out on privacy concerns and more limited features in comparison to some desktop wallets.
Some wallets like BlueWallet, Stack Wallet and others allow you to add a custom server, such as an Electrum server (electrs, EPS, electrumx etc) connected directly to your full node.Optionally, you can enable Tor on these mentioned wallets. It's always best to prioritize wallets that offer privacy-enhancing features.
Zack Herbert CEO of Foundation, the company behind the well known Passport line of wallets recently shared his belief that "seed phrases may soon be obsolete". He said that Foundation is already working on developing of the seedless wallet. It should be mentioned that other companies have already entered this space. Notably, Tangem and Cypherock X1 offer alternatives to seed phrases. I have Tangem 2 
In theory, the seed would be split into three parts - two on physical cards and one on the user's device (like a phone). But what if I lose one of these cards or the phone? I'd still need to exercise the same caution as with multisig wallet keys or shared Shamir backup shares.The user will still have to save things and it won't change much that people will continue to lose things.
Do you have an official statement from Passport about this? I checked their blog but couldn't find anything related.