You seem to be interested in identifying and characterizing different structures involving an obligation that was not fulfilled.
I think it advisable to add a direct object to those sentences so that their sense can be complete. As they are, something seems to be missing.
1) Debió entregarle el dinero: this has two possible translations (let's imagine the subject is female and the recipient is male):
1.a. She had to give him the money (and she gave him the money).
1.b. She should have given him the money (but she didn't). In Spanish, this can also be expressed as follows: Debería haberle entregado el dinero OR Tenía que entregarle el dinero OR Tendría que haberle entregado el dinero (pero no lo hizo).
2) Le hubiera entregado el dinero: this expresses a wish (or regret) about something that did not take place in the past:
2.a. If only she had given him the money.
If there is a tacit condition, sentence (2) may express a hypothetical result:
2.b. What would she have done if she had had the money? (¿Qué hubiera/habría hecho - ella - si hubiera tenido el dinero?)
She would have given it to him. (Se lo hubiera/habría dado.)
My conclusion is then that both "Debió entregarle el dinero" and "Le hubiera entregado el dinero" can express regret about a past obligation that was not fulfilled. Each structure has in turn a meaning of its own: "Debió entregarle el dinero" can express a past obligation that was in fact fulfilled, while "Le hubiera entregado el dinero" can form part of a conditional sentence to express a hypothetical, counterfactual result.
I admit that the non-native speaker may be confused by the possibility of "Debió entregarle el dinero" expressing either a fulfilled or a non-fulfilled obligation, but unfortunately Spanish allows both possibilities. The context will define which is true in each case.