The key at the top left of the keyboard is the Home key. As far as I know, an iPad does not need an Esc key. At least I have never missed the Esc key on the iPad. Yes, there are workarounds. You can ask the AI.
1. Yes, this keyboard is compatible with a pre-2019 iPad Air 2 because it uses the Bluetooth connection, which is supported by this device.
2. No, this is not a QWERTZ keyboard, it is a QWERTY layout adapted to Apple devices.
DE presumably, but this has not yet been confirmed. US layout will probably not be possible at all. However, it may be offered by a third-party retailer, over which we have no control.