ScreenFlow team has rewritten their codec into arm (Neon) from intel (SSE).
You can grab your copy from this link:
9.0.6- Improvements & Fixes
ScreenFlow is now fully compatible with Apple Silicon hardware and macOS 11 Big Sur! Enjoy incredible performance & battery life on M1 hardware.
● IMPROVED – ScreenFlow 9.0.6 is now a universal (Apple Silicon + Intel) app. All SSE and AVX2 code
has been ported to NEON for best performance
● IMPROVED – Improved look of welcome window on macOS 11 Big Sur
● IMPROVED – Updated app icon for macOS 11 Big Sur
● FIXED – Fixed crash on macOS 11 when selecting a custom mouse cursor
● FIXED – Fixed position of timeline scrubber on macOS 11 Big Sur