If the baby is sleeping fine and the poop is not bothering the baby then there's no need to wake the baby up from sleep to change their poop diaper.
There's nothing wrong with letting a baby sleep in a poop diaper and it's not neglect as long as you change the poop diaper after the baby wakes up.
I've let my kids sleep in poop diapers at night or when they were napping and then changed their diaper when they woke up.
Just apply some diaper rash cream to the babies bottom and some baby powder and the poop should not cause the baby or toddler to get a rash.
Even wet diapers don't have to be changed right away and you can let the baby sleep in the wet diaper and a poop diaper and there's nothing wrong with it.
If the poop or pee diaper is bothering the baby then they will wake you up by crying and if they do then you should get up and change the poop diaper.
But if they are sleeping just fine in the poop diaper then there's no need to change the babies diaper at night and letting them sleep in the poopy diaper is just fine.