phone not turning on, need the data recovered, how?

Hi,

OnePlus phone won’t turn on. after taking it to the OnePlus service centre, they said they would have to flash it to fix as it could be a motherboard issue. Unfortunately, we had not taken any backup of the data, the phone has many childhood memories as photos and videos. we would like to recover the data somehow, either by fixing the phone without losing data or by just extracting the data. could you please let me know if it is possible through your tools and guides? if so how?