When you are connected to internet you have to be very careful no matter what device we are using,IOS,Android or windows or any other operating system because even reputed softares in the pasts were found that they are tracking user's privacy information.Best solution is hardware wallet.
Now even a hardware wallet does not give any guarantees because there are some cases of hacking start to appear or some kind of inside replacement of address.
I wrote about tampered hardware wallet such as Ledger, and trezor that has been sold commercially in online shopping store like Amazon and Aliexpress. There have been cases where funds in hardware wallets are missing unexpectedly, it is true that there might be some altered stuffs in it to contain the fake address, malicious software, or they know the private keys.
I think in order to safely store cryptocurrency, you can use some kind of smartphone that will never connect to the Internet. it will be harder to hack it.
More likely a 2nd phone, it might be good but it is better if you have a secured hardware wallet bought from legit producer so you can be sure of your cryptocurrencies.