I didn't find any solution to get my old Razer Ripsaw (non-HD) capture card to work on Windows 11, so I tried to find my own solution:
1. Disable "Core Isolation" (so "Ripsawx64.sys" driver can be installed)
2. Install Razer Synapse 2.0 (I installed synapse 3.0 and thx spacial audio too but I don't think these apps are necessary. Uninstall all Synapse apps if you tried to install them before disabling core isolation)
3. Download and open DPCLat.exe (to fix the audio on OBS Studio). Credits and download in https://www.youtube.com/watch?v=StAFNBmPH3o
pd1: This leaves "core isolation" disabled on your windows.
pd2: Tested on Windows 11. Not tested on Windows 10.
I hope it works for you :)