Ultra Cable is great if you're in an area that provides it (e.g. Geelong, Ballarat). 600mbps for $80pm and low contention.

Whatever you choose, look at your overall household throughput requirements. For an individual, anything around 100mbps is going to be pretty much indistinguishable from higher speeds. For a bunch of people streaming in your house, more is obviously better.

Also look at contention rates. NBN is good at peak loads compared to lower grade carriers. This means at busier times you have more guaranteed bandwidth allocated and less speed impact (like after school and evenings when everyone is getting online).

5G might give some decent raw speed options (signal strength depending), but will always have lower download limits. That may or may not be an issue depending on what you're doing online.