Вот официальный ответ производителя конкретно для этого SSD:
Dear Neo Anderson,
Do you have usage capacity? That’s can show on crystaldiskmark, from the crystaldiskinfo, we notice write to the NAND is 1.5TB, that should running out TLC cache space, if you can backup all data and try secure erase it can recovery the performance
Refer is here: https://www.tomshardware.com/how-to/secure-erase-s... 
