You are out of date.
You do not need to adopt sibling groups. Some people do, many don’t. SS like siblings to stay together but know it’s often impossible.
There were about 60 under twos up for adoption in the North East last year.
More children are removed from their parents earlier than was the case a decade ago, mainly because children were being removed too late to be adopted and get a fresh start. Some children are removed at birth or soon after (usually because one or more siblings have already been removed).
Adopted children are always (rightly) classes as vulnerable, but children removed young would not normally be traumatised.