At that switching rate and power you should really be thinking GaNFETs, not silicon devices.
You might be better dropping to 100kHz or lower where switching losses won't cripple you.
80V is also high enough to cause a lot of issues with protection circuitry, but low enough that
IGBT's are rather inefficient (and they run slower too).
If you have a history in switch mode supply design, you'll have a chance of getting this working,
otherwise expect a learning exercise and buy plenty of spare parts (and wear eye protection,
MOSFETs at high power fail by exploding).
You will need gate drivers for fast switching, get high-low MOSFET drivers that have dead-time
enforcement and protection built it, and add zener's across gate/source of the MOSFETs. Use
two switching devices and synchronous rectification, not one switching device and one diode,
I reckon.