I think there are different places where shared paths make sense versus separated bike paths. Along the road at the start, and the road nearer the end (before turning off down the hill), separated bike paths seem appropriate, and it looks like there's ample room for them. But the underpass and path through the park that connected them is perfect for a shared path. Making it a bit wider in the last section would be good, but it's otherwise quite a good solution.

The video doesn’t quite capture the extent of Greater Brisbane’s shared path network of unofficial bikeways that will technically also requires e-bikes and e-scooters to ride 10km/h.

Well, part of this video shows one of those. The Cabbage Tree Creek Bikeway it uses while going under the underpass is one of these so-called "bikeways" that legally counts as a shared path, where the 10 km/h limit would apply. But yeah, it definitely didn't focus on that element.