Fiji Layover / Any experience traveling to ( or through) the island?

Flying back from Sydney to the U.S. next week and I have two layover options in Fiji (Nadi): a short 2-hour layover or a 10-hour one. I’m leaning toward the 10-hour layover so I can get out and explore a bit; maybe hit the beach or see some of the island.

Has anyone transited through Fiji before? If so, did you need a transit visa in advance, or was it handled on arrival?

Also, for those who’ve done a long layover and rented a car, which rental company would you recommend? I’m seeing Avis at around $120/day and Payless for $50, but I’ve read some reviews saying Payless adds on surprise charges for insurance and a cash bond. Would love to hear about your experience.

And if you’ve spent time in Nadi during a layover, what are some must-see spots or things to do nearby? Any recommendations on what to check out or what to avoid would be super helpful. Just trying to make the most of the time if I go with the longer layover. Appreciate any advice!