Install Neff KI6873D40 in IKEA Metod kitchen?

You are right. It would work. Below an 80 cm door and above a 120 cm door. Then a base of about 14 cm with ventilation must be installed below, which is load-bearing and closed at the front. Above, there is basically no compartment left.

That's just craft stuff. Ikea cabinet or another kitchen. If then properly. K.

The refrigerators from IKEA unfortunately have energy efficiency classes that are too poor ...

Calculate the difference in consumption compared to your desired model over 10 years of use. The discussion will probably be settled then.