Tangem seemed like an interesting concept but the key leakage is the worst thing that a hardware wallet can do. If we agree that a hardware wallet is a device that is supposed to keep your keys safely on said device, Tangem doesn't meet this requirement. It might have been for a short time and the problem might have affected only a small part of their users, but it's a huge no-go.

Even Electrum mobile has a weird concept that can be considered as coin control. They allow you to freeze coins and addresses, leaving the one/ones you want to pay from unfrozen. Like I said, a weird way to implement coin control.