macOS 11 Big Sur is supported from Serato Studio 1.5.7
You can find the latest version of Serato Studio software here:
IMPORTANT: Apple M1 computers with macOS 11 Big Sur are also supported when using Serato Studio, but please note that Live Streaming, via the Make Audio Output available to other applications feature, requires Serato Studio 1.6.0 and above - where the newer Serato Virtual Audio driver replaces iShowU for all macOS users.