Here is a great Ant Bms where many use and it fits exactly in Qulbix Q76r frame.
https://de.aliexpress.com/item/Smart-Display-300A-200A-150A-100A-70A-Lithium-Battery-Protection-Board-Balance-BMS-Coulomb-Meter-Lithium/32826820690.html?spm=a2g0s.9042311.0.0.1d174c4dIo0EFi