Using a dedicated phone as "hardware wallet" Is there anything inherently insecure about using a dedicated Android phone as a &quot;hardware wallet&quot;?
A dedicated phone implies:

a clean ROM without gapps, e.g. GrapheneOS, Lineage OS without root, etc

full phone encryption enabled

no other apps installed apart from a wallet app such as Mycelium, Breadwallet, GreenBits, Samurai, etc.


I realize that the majority of Android phones don't have (yet) a secure element like trezor or ledger devices, and that system apps might have unlimited privileges, but what are the main issues or specific attack vectors to be aware of in such a setup as compared to dedicated hardware wallets?
My understanding is that physical access to a trezor or ledger is useless if the attackers don't have the pin or passphrase and that these devices are built in such a way as to make hardware extraction of private keys impossible or financially unfeasible.
Is a comparable level of security achievable with an Android device with full phone encryption?
Also, does setting a pin code in a software Android wallet mean that the private keys are actually going to be encrypted or is the pin just for opening the UI?
Any data on which wallet apps protect the keys in a way which makes their extraction impossible without the pin code/fingerprint?
Resources

https://forum.xda-developers.com/t/guide-tweaks-android-security-hardening.1954513/

https://www.reddit.com/r/GrapheneOS/comments/bddq5u/os_security_ios_vs_grapheneos_vs_stock_android/

https://www.reddit.com/r/privacytoolsIO/comments/6kyteo/aside_from_copperheados_what_is_the_best_android/
Is a comparable level of security achievable with an Android device with full phone encryption?


Short answer: No. This doesn't mean an Android device is bad, there are less secure ways to store bitcoins. But it does have more attack vectors than a hardware wallet. 

You can add whatever encryption to the phone you'd like, but ultimately if that device can connect to the internet, there is risk that some malware could be loaded to it. A hardware wallet is not at risk of this type of attack, the secure element is kept isolated from the internet.

For example, if screen capture malware is loaded onto the Android device, and it snaps a screen grab of your seed phrase, the encryption methods won't matter at all. This sort of attack isn't possible on a hardware wallet.