I had a very good experience with Opera during my stay in Australia. It was about two months back when I traveled to Australia for a business trip and in my free time I was actually using the VPN to streaming beIN sports to watch football matches. The only problem I had faced was with the speed. For that I had to switch to different servers and it worked fine. I would highly recommend Opera as it is a good solution for any kind of VPN use, however, if you want to download torrents in Australia, then I would say that try some other VPNs as it is not as effective as expected. For Netflix also, you may find some issues with the VPN, so I had to switch to NordVPN for that after reading a detailed guide on AU VPN here: https://www.reviewsdir.com/best-australia-vpn/
Though the guide doesn't cover Opera VPN, but there are options that can be useful if you are a power use of a VPN.