There is no TB port on my MacBookPro yet, can I use this ext.FP with an Apple adapter (Thunderbolt to fireWire - https://www.apple.com/ch-de/shop/product/MD464ZM/A/apple-thunderbolt-)
No, that is not possible. The adapter mentioned also requires a TB connection. Without a Thunderbolt connection, this hard drive makes little sense. You can operate it via the USB-3 connection. However, it is not worth buying the more expensive Thunderbolt version.