If you are borrowing from adoption studies and applying findings to assisted reproduction you are looking at the wrong evidence base.
Children born through donated eggs are never seperated from their birth/gestational mother, and their progress from the potential for life, to life, is entirely contingent on the biology of the recipient, and an intricate exchange between them, over 9 months of pregnancy, which as mentioned earlier, changes both for ever. Not acknowledging these as biological acts of motherhood is perverse. Children who are told, are clear on their biological origins, and the circumstances of their conception, face no dislocation from their birth mother.
Genetic heritage remains a very, very important issue for children (and their mothers), but needs understanding in its own right, and not entangled with the other issues typically involved in adoption, which are not present in egg donation. I can't link, but this is open access:
A Longitudinal Study of Families Formed Through Third-Party Assisted Reproduction: Mother–Child Relationships and Child Adjustment From Infancy to Adulthood, Susan Golombok et al, Developmental Psychology, 2023.