And in case is stolen, you have a good amount of time to move your coins to another wallet.

In other words, restore the wallet to a different device using the master key, and then transfer the coins?

If the air-gapped phone is stolen, is guessing the PIN to unlock the phone the only thing stopping the thief from spending the victim’s money at that point?

and you can always just use an f-droid repository if they only publish releases there.

So Obtainium users can install F-Droid apps through Obtainium?