Crying it out is not damaging to babies as long as they don't cry it out for too long.
Most babies will only cry it out for 30 to 40 minutes and then drift off to sleep.
But if the baby cries longer than 40 minutes then you should go in to comfort them and check on them.
Although "crying it out" as a sleep training tactic is not recommended for newborns, if you're about to start crying hysterically, it's OK to put baby down in a safe space for a few minutes to give yourself a break.
Crying it out for short periods of time will not harm the baby but if the baby is crying too long then they could suffer brain damage or other health issues.
If a baby is allowed to continue crying for too long then the excessive crying can eventually lead to brain damage in the baby.
It's always best to go check on the baby and comfort them even if that's all they need.
Babies are a huge responsibility and require lots of work and love from the mother and father.
If the baby continues to cry for longer than an hour and hasn't fallen asleep then go into comfort them or check on them to stop the crying.
But you can let the baby cry it out if it only lasts an hour or 2 but any longer than 2 hours you really should go into check on the baby.
Babies will tend to cry a lot even during the middle of the night for the first 6 months of their lives and you won't get much sleep but eventually that will go away and they'll cry less.