I visited the Margaret river region in 2020 just before lockdown. It was my second and not my last visit. You will need a car as it’s a few hours south of Perth but it’s an easy drive on fairly quiet roads. There is so much to see and to do. Bussleton is a must..pure white sand and the longest pier in the Southern Hemisphere with a wee train of you don’t want to walk it.
There are sooo many beaches to visit a well and none of them are busy.
Additionally dotted all around the region are numerous vineyards and cellar doors plus cheese and chocolate outlets to visit. They all do tours and most have beautiful restaurants serving fresh local produce. We stayed in Cowramup at a friends house but there are lots of truely lovely places to stay