NSW, Aus offers SIX Maps: https://six.maps.nsw.gov.au (this offers very good imagery of the NSW areas, better than google)

That's the easy-to-use-maps.

There's also the aus-wide https://nationalmap.gov.au where you get basic satellite maps with the option to add various datasets and even daily maps from Landsat 2A

There's also ELVIS foundation spatial data https://elevation.fsdf.org.au

There's don't really cover hiking trails that much, etc. There's more general purpose mapping applications.

It's also possible to find various topographic maps in static form somewhere on the government sites.

Councils are the ones that provide the hiking trails, etc. so it depends on the locality. The Northern Beaches council for example provides an interactive trails map, but most have static maps.