Are you working with a landscape designer? They could help you envision a new retaining wall and grass/plantings to all work together. As far as wall materials go, I’d do a stacked natural stone of some type and put plantings along the top of the wall.

A slope with good landscape cover so it doesn't wash into the drive would look nice.

Since the house is a separate stricture within itself we could do a rounded e entry of stone and take all of the yard out and make it a circular drive w tons more space for parking and still have a decorative entrance w planters and shrubbery etc.... lots of space to do anything you want