You shouldn't need to disable SIP. That disables a bunch of protections in macOS, and in multiple years of using the S3L, I've never had a need to do so.
The S3L can be finicky, and I too have experienced problems like you are mentioning. I would check a couple things.
- Is Port A of the S3 console plugged into Port C on the E3 Engine, and is the computer plugged into Port B of the S3 console? Any other configuration can result in AVB issues.
- Which version of macOS are you using? High Sierra is definitely a bad choice, but others (all the way through Big Sur) work well for me.
- Reopen the Audio MIDI Setup > Network Device Browser and verify that the E3 Engine is enabled as a virtual audio device.
If you want to troubleshoot further, you can use the avbutil command of macOS to see if the E3 Engine is visible at all. I've written about that tool on my wiki (
https://wiki.forestent.com/Avbutil).