So far I've found that VSL's software is behaving perfectly normally in Big Sur; it's other aspects of this MacOS that lead me to getting annoyed, nervous and uncomfortable. It's hard to foresee myself doing anything creative in Big Sur any time soon - the muse just does not pay visits in those kinds of circumstances. (Remember when and why Macs were easily and by far the favoured choice of creatives? Man, I miss Steve Jobs.)
By all means upgrade now; but as Paul recommends, I too suggest upgrading into a partition (or external bootable drive), ensuring you can easily dual-boot between Big Sur and your current MacOS build. I'm certainly not suggesting this is necessary in case VSL software misbehaves in Big Sur; I've not found any evidence indicating it might. I'm advocating this approach so that users may avoid a possible risk of creative block lasting for, well, who knows how long? I'm much happier and more relaxed being able to dual-boot, not only because I can go back to High Sierra easily and get on with my work there, but also because I don't feel trapped in Big Sur - I can limit my time in there to small doses.
(Optimism alert!) Here's hoping MacOS Monterey turns out to be a far more congenial platform for our creative work and enjoyment.
