Hi Erwu117,
Which LDO exactly are you talking about? Is it LDO on the OAK-D-Lite or the PMIC on the RPi?
Suppose it is on the OAK-D-Lite, best would be if you can take a photo and point me to the component that is overheating or you think is causing troubles and we can let you know the PN and help with assisting you with ordering.
TL;DR: If you can explain it a bit clearly to me what causes issues we might figure out something.
Thanks,
Regards,
David