I have a more permanent solution I’ve sent via PR to Victron linked in the ticket here: Add support for SeeLevel II Bluetooth integration for 709-BTP3 · Issue #1508 · victronenergy/venus · GitHub
However, when I couldn’t move forward on my own, I built a Python revision: GitHub - TechBlueprints/victron-seelevel-python: SeeLevel 709-BT Bluetooth to Victron Cerbo GX for monitoring RV tank levels, temperatures, and battery voltage which you can use now.