Got bored of typing it in everytime
This script uses OMC Decoder from Soul Reaper
One liner:
cd ~ && pkg install tsu && curl -so decode-csc.sh https://raw.githubusercontent.com/fredinj/decode-csc-termux/main/decode-csc.sh && chmod +x decode-csc.sh && sudo bash decode-csc.sh
*Only tested with M21 and M31, paths might be different in other devices