Switching 120VAC over 70A safely
80 Amp is still doable with a contactor.
example: Schneider Tesys D goes up to 250 Amps.
The LC1D80AQ7 does 80 Amps, if you connect them in parallel for AC-1.
Beyond that you will go into motor operated circuit breakers.

Read the instructions of your products with these currents!
For example, paralleling the contacts of above contactors requires special jumpers and connection order. And they have a maximum operating count per hour and a minimum interval.