As for cutting off and replacing the entire front section (engine bay), don't even think about it! You are then into the alignment territory by joining two separate sections to end up within all specs, not easy at all.
But the damage may actually look worse than it is, the right corner has taken most of the impact. Supposed the frame is not twisted and no damages further back, doors jammed etc.. it should be reparable by changing inner sheet metals and the front part of the main frame beam. But it's a loooot of wrenching and an endless search for all the NLA body panels, headlights etc... As described already the ROI is very, very low.