Open source wallet can has malware included. Only open source wallets are recommendable. Because a wallet is open source does not mean it is not vulnerable to attack, but the ones that has been tested and seen good to the community are recommended. Example are Electrum and Trezor.

Close source wallets are not recommendable at all, you do kit know anything about the code used to build the wallet, the public do not know it, only the developers knows it. Storing your coins on such wallet is dangerous and does not comply to how crypto should generate keys and addresses if talking about freedom. You must know everything about your wallet included the code used to build it. If you do kit know how to, at least you can ask on forum like this.

Bluetooth is not recommendable. Better ro get a USB hardware wallet, but not still that recommendable, the best is to just make use of only QR code which is better. Have you seen a device that it's Bluetooth will always be on always? I haven't seen such device before.