The bootloader unlock tool for the Realme XT is now official with instructions for use being made available on the Realme Community page. While the bootloader unlock allows Realme XT users to install custom ROMs, it disables official OTA updates and also downgrades the Widevine level from L1 to L3.
https://www.notebookcheck.net/Realme-XT-bootloader-unlock-now-officially-available-but-there-s-a-downside.460354.0.html