discutir vs comentar
'Discuss' is a false friend. Discutir means to argue. Comentar is to talk through, remark on or mention.
discutir
To argue, quarrel — a heated exchange.
Discutimos por dinero.
We argued about money.
A row. Discutir por + reason.
No quiero discutir contigo.
I don't want to argue with you.
A common phrase to avoid conflict.
Han discutido otra vez.
They've had another argument.
A couple or family quarrel.
comentar
To discuss, comment on, mention, talk over casually.
Te comento una cosa.
Let me tell you something.
Conversational. 'Te comento' = I'll fill you in.
Comentamos la película al salir.
We talked about the film on the way out.
Casual discussion of an experience.
Nadie comentó nada.
Nobody said anything.
Comentar = to remark. 'Comentario' = comment.
Tricky bit
'Vamos a discutir el contrato' sounds like you plan to fight over it. For a neutral talk, use 'hablar de' or 'tratar'. In formal Latin American contexts, 'discutir' can be neutral — region matters.