I was getting some checks cashed at the bank, when I get home I count it and low and behold I had a significant amount over what I was suppose to receive.

This could be the same analogy as finding a wallet on the street. What does a Satanist do in this situation? I know Maxine said she found $20, enough to feed herself for the day. But I am not in that position, at least not yet, thanks to the Rona.

I definitely could have used the money as I am not rich by any standard, but I did end up returning it. Knowing full well that if any Jew was in my position or even a completely rich one would more than likely keep it.

What does it mean to be noble in these times? I know we don't try to keep "morals" from limiting our magick, am I a fool for returning the money?

I would return a wallet unless the name on the ID is schlomo cohenbergenstein.
If I find money on the street(those sweet sweet 50euros banknotes) I keep it.
If the bank gives me more money either the bank took all that money from your own deposit or it made a mistake, in the latter I don't really care, banks are jewish owned, they got all the money they want.

Being noble is not backing down on your principles no matter what.

Most banks audit themselves all the time. So they go back and check everything they did. If the bank gives you too much, they will almost certainly realize that they did that, and they will try to get that money back from you. If you don't give it back, they can charge you for fraud and put you in prison. So good idea that you gave it back. Maybe there is a chance you could have gotten away with keeping it, but there is a bigger chance that they will notice.