Before attempting any software modifications, you need to understand the hardware. The B760HS3 is typically powered by an chipset, coupled with:
Download a clean "Amlogic S905L" Android TV 9.0 or 10.0 IMG file. Look for files named B760H_9.0_unlock.img or s905x_atv_10.img . Zte Zxv10 B760hs3 Unlock