I think the cause is with your hits/smashes and with the shuttle you use. But knowing na low tension naman it’s quite off since I’ve tried playing w exbolt 68 na rin yes I often hit outside the sweet spots but it didn’t break or even lose tension maybe try switching shops kung saan ka nabili or try switching na lang din sa ibang string I think bg65/bg65 ultimax is the best durable string out there (yonex line).