Keeps TWRP installed after an A/B OTA.
This is NOT a normal module – it will NOT show up in Magisk Manager’s installed modules list.
Flash this script zip after each OTA has installed, but before you install Magisk to Inactive Slot from Manager
Initial install should be from the Downloads section in Manager, then subsequent flashes can be from the Modules section using the + button and selecting the downloaded zip from internal storage.
Download TWRP A/B Retention Script Magisk Module
This module is not available as a downloadable zip file but you can get it easily from the Magisk App.