Unless you have enough inbound liquidity on lightning for either of those wallets there isn’t a cheapest way, you will have to do an on chain transaction to open up a channel with enough liquidity.

You can still just download the apk

No need to be paranoic.

1. save you phoenix seed.
2. Uninstall from app store (because is linked to yout account)
3. Install app from their github, without any fucking app store
4. Restore from seed.
5. Done, be happy and ignore all the shit.