TL;DR From my initial testing, macOS Big Sur works great with the S3L and S6L.
When I first started testing, I was doing so through the PreSonus SW5E, which resulted in the clicky AVB audio problems I’d experienced with macOS High Sierra (see my previous blog post on the topic.) After upgrading the firmware on the SW5E, everything worked great.
|1 Feb 2021||macOS Big Sur 11.2 RC (20D64)||2020.12.0||Yes|
|23 Dec 2020||macOS Big Sur 11.1 RC (20C69)||2020.11.0||Yes|
I’ll track macOS Big Sur here, as well as my larger combination list on my wiki (https://wiki.forestent.com/Avid_S3L_and_macOS).