I don't know the MBB situation but I have some tuppence.
Many of my American relatives have adopted & others gave up babies for adoption.
USA adoption is so so so (SO) different from UK system.
USA: many adoptions are from birth, the baby doesn't bond with foster carers for months before being wrenched away to adoptive parents. Nowadays, the adoptive parents usually meet the birth mother and are part of a support team to make the process as least painful as it could be.
that's why I always find it so weird that adoptive parents in UK live in fear of angry or dangerous birth parents. That isn't experience at all in my family.
for example:
Cousin J (birth mother) met the adoptive mother who was there at the birth & adoptive Mom cut the umbilical cord. J and family received yearly updates about the adopted away baby as she grew up (now 25yo).
So idea that the adopted kids are inherently traumatised because of their backgrounds and only entered adoption system because of neglect and/or high risk of harm to child and the adoption was compulsory and the kids are inherently damaged as a result etc.... not the norm. All that must happen too, but it isn't how a single adoption happened in my extended family. Actually, my nephew (now 33yo) has older half brothers who were in foster care from age 2yo, but not adopted. I never met them but their birth mother was proud of how they turned out, reckoned she had always done right thing to reliinquish them.
Cousin who is now... 29yo? he and wife adopted earlier this year after wife had a miscarriage that devasted her. Adopted From birth.