There are a few to choose from regarding the pros and cons of letting Andreas Christensen go. All in all, it is his choice to make, and it seems like he's made it. No, he does not owe the Chelsea fans anything, and no, it is not a sign of betrayal. I am not a fan of how the whole contract saga went down. However, I am more than happy to take the loss.
It truly is a loss to lose a player with such a high ceiling, but we cannot keep living in regret of our past mistakes. Losing Salah and De Bruyne was a massive blow, yes. Losing Christensen is a gamble.
Whatever he decides to do in the end, we wish him well.