Yes, pete, "death" can have different meanings according to the context, as you say. Physical death, moral death, spiritual death. Death in some sacred traditions is also seen as a gateway to rebirth (either in the physical sense or the spiritual sense...or both at the same time).

I understand how many Christian believers feel that they "benefit from that substitutionary atonement spiritually by being forgiven and reconciled". And I respect that. I also realize that there may be something to it. In my own case, I think that God's forgiveness and love for each one of us is always there, just like the Sun (or the Son) is always shining...even at night and even behind the clouds...but that a person can't really benefit from God's forgiveness much unless they repent of their own negative behaviour (which means they open their hearts to the truth about what they did, and with genuine repentance, and they try to change for the better). This is a process people may go through many, many times.

And people need to forgive others if they expect to receive forgiveness!

In either case, if you shut yourself inside a darkened room and simply refuse to ever open the door and go outside...you will never see the sunlight! That is the situation of someone who refuses to forgive others and refuses to repent of his/her own misdeeds. What is repentance? Simply realizing one did a wrong thing, regreting having done so, and resolving not to do it again if at all possible...plus, repairing any damage done, if at all possible. To express that repentance to God is a very powerful act, but no one will do so if they think there is no God...though they might express it to another person in the form of an apology. That too is a powerful act, and requires courage.