I don't think changing the user agent string affects which codecs or device drivers are available on the client. If changing the user agent string "solves" the

I don't think changing the user agent string affects which codecs or device drivers are available on the client. If changing the user agent string "solves" the problem, then the problem is most likely with the site - especially if the same problem and solution exist between different browsers. They are probably assuming some capability is absent instead of testing and gracefully degrading. I wonder what happens in Windows 10 with a user agent mimicking a Linux environment. Does the site slow down? If so, the support bot can't brush it off since it's a supported operating system.