It's all in the manual - I don't know what SW version you are running, but here's the latest - what you are looking for is on 234:   https://www.cisco.com/c/dam/en/us/td/docs/telepresence/endpoint/ce913/sx80-administrator-guide-ce913.pdf   You have t...

The resolution/framerate on the HDMI output is settable - if I'm not mistaken that is 1080/60 by default - perhaps try changing that setting? I don't know what your splitter supports. 

Roger is right - the SIP parsing is how OBTP works. As far as Zoom stating RoomOS isn't supported, it definitely works, I have been on Zoom meetings with a cloud registered endpoint. RoomOS and CE are not much different. May I ask why are you opposed...