@lina20230222 It is shambolic the way they organised this VPN offering. They advertise it everywhere as being built inside the browser and you WONT need additional software installed. However in yours and my case, Opera asked to install an updated version of "VPN Pro App" because the browser couldn't do it by itself. On the iPad, Opera browser doesn't have a VPN feature. It is just a skin on top of Apple's Webkit API.
I managed to dig the system requirement for Opera VPN Pro to work. Here it is and has a big clue on what MacOS version is needed : "Opera VPN Pro is available for Windows 8 and above Laptop/Desktops or for Mac devices running MacOS 10.15 (Catalina) or later. To use it, you need to download current Opera Browser or Opera GX for Desktop. Opera VPN Pro is currently not available for Windows 7 devices. Please note that VPN Pro is not yet available in Opera Crypto."
However when I move away from my MacOS High Sierra to a Windows 11, I sure will buy their VPN Pro because I see it as a way to support Opera. Shameful they won't support older Operating Systems and won't give a reason why.