Confused on approach to kill lawn if wanting an indigenous garden

New to the gardening game…

We have a backyard with a lot of lawn we want to remove/kill. We are part of the Melbourne Sandbelt (the soil is basically just sand), and as such I’m nervous that solarisation will kill any beneficial microbes in the soil, but that sheet mulching will introduce too many nutrients for the indigenous plants to thrive. The goal is a stick/mulch look around the shrubbery with sandy, log-bordered paths… Is the only realistic option to just rip the lawn up (we probably have 300m2 of lawn, so that would be a great winter-warming exercise!)?