If you still wish to attempt using GravityBox or its modern equivalents on Android 13: using Magisk. Enable Zygisk in Magisk settings. Install the LSPosed module (Zygisk version) and reboot.
: Focuses heavily on the visual aspect (Material You colors, brightness slider styles, and font changes) and works excellently on Android 13. Firefds Kit gravitybox android 13 free
Since GravityBox is no longer actively maintained for newer Android versions, users on Android 13 typically switch to modular, specialized tools that are updated regularly: If you still wish to attempt using GravityBox