Hi Paul! Thank you very much for your answer. This next to Andreas' reply helped me a lot.
In my reply to Andreas I provided some details about the original post in that other forum I referred to. I don't think the statement of the original poster was meant as criticism regarding unbound - however his statement haunted my mind 😉 Thanks to your explanation my trust in unbound is back and I will gladly continue using it on my Pi as my local DNS resolver 😊
