Waxes or sealants will protect your cars paint from etching, fallout, watermarks etc but won't really prevent washing induced swirls but will make them a bit less noticeable.
There is several things you can do to minimise damage while washing such as using a snow style foam wash to pre rinse off as much muck as possible before touching the paint, using the two bucket method to wash & using thick clean microfibres to wash & dry the car rather than traditional sponges or chamois that offer no gaps for any debris.