I’ve seen two approaches suggested:
1. minimal packing so it’s obviously a bike and will therefore be looked after (yeah right) and if that doesn’t happen you can easily see the damage
2. buy/hire a bike box
I tried #1 in the past. I put pipe lagging on the frame, crossed my fingers, and got away with it. It was an mtb that regularly got thrown down hillsides by me so I didn’t care about a few more scratches.
On my last trip I took my road bike and went for #2. The box was £40 to hire and it was all far less stressful. It does take up more room in the car but less than you think. And because it’s a box it’s easier to pack on/around in the car.
All depends how much you value your bike.
EDIT: there are lots of places to hire bike boxes. Look on ebay and you’ll probably find someone near to you who’s trying to recoup the money they invested in buying their own box.