@plattsad Well, to answer my own question kinda, I did find a way to make the installer work, but it makes no real sense.
A lot of people reported SSL issues with firewalls, VPNs and software apparently conflicting. So I actually enabled the bitDefender VPN and after that the installer had no difficulty downloading Opera. The thing about this is that the windows 11 VM with a shared network connection had no install issues ... so I don't think it was a firewall.
Just of odd!