The Disney+ issue is also present in Ventura with the latest nightly build of Open Core that I have installed.Same here, neither Netflix nor DisneyPlus work with Safari or Safari Technology Preview but are ok on Chrome.
Apple TV app and Photo Booth work fine.
As I personally don't use a web browser to use my streaming services with, I wouldn't even care personally. For the sake of the forum though, I did look for myself and did find the issue present here as well. Netflix, I haven't tested.
To be fair though, I have used streaming services in the browser, but mainly so I can use a keyboard to search for things, but viewing for me is typically done in the home theater so I get the multi channel audio, and other features such as HDR, or I use the mobile apps on my iPhone, but primarily TV. The other thing is, I've never cared for Safari personally, I just feel Firefox and Chrome are just better overall, especially if you want cross platform.
Hopefully the issue is resolved for those who need / want it by the official OCLP 1.0.0 release though.