Roberto Firmino has been playing at Liverpool since 2015, it's true as you said that Firmino knows the Liverpool game better than Darwin Nunez.
After all, Firmino is 30 years old, which means he is more experienced in controlling emotions when playing. Unlike Nunez, whose emotions are
easily provoked by opposing players when frustrated that he cannot score a goal.
Agree. Firmino already proved it in many matches that he has good emotional control. He rarely got cards, especially red cards. Even, I never saw him get red cards as far as I watched Liverpool matches previously. Honestly, I think Firmino is still much better in terms of winning mentality. Instead, the absence of Nunez may make Liverpool game better since they have better cooperation with an old player.