Yes, I have run Fallout New Vegas from the game launcher, changed some settings, played for 10 minutes, and the registry does recognize that folder as the game's path. I have also manually chosen my Fallout NV folder in Vortex just to make sure.
No problems with extensions, at least as far as I can tell from a first glance (screenshot attached.)
Also, to reiterate, I have successfully used Vortex before on this machine, using this same internet connection, but with another game. It's been months though, I don't recall any similar errors or any bad experiences.
I have disabled the firewall, tested it, enabled it and made exceptions for Vortex, and so on. Same result. Everything else on Vortex, such as in the dashboard, seems to connect to the internet well, such as checking for updates, logging into my account, Latest News, What's New, New Files, and so on.
What free VPN would you suggest me to try in order to troubleshoot this?