@flippertyop
I didn't say they would have more issues than other children. They have been bought but they may not feel they have been bought. I don't think it would be right to ask them, given their ages, that would be wrong.
They have the full medical history of their genetic mothers, well that's good, but they may want to know more than that. I'm assuming that the eggs that made these children were not under U.K. HFEA and they won't have the name and details of their genetic mother/mothers? Under U.K. law anonymous donor gametes are not permitted. This sounds like a commercial arrangement, perhaps based in the US or the Ukraine? Most likely US given the age of the children.
These children you mention may or may not experience genealogical bewilderment, like some other donor conceived and adopted children. Who knows? They only know one of their mothers, the commissioning mother who is their social parent, not their biological mother nor their genetic mother. I'd say that creates a situation where genealogical bewilderment is more likely, rather than less likely. This can be triggered in adulthood, particularly around the time they wish to start their own biological families.
We also don't know anything about the mother, the women who have birth to them. The arrangement she entered into may have been a friendship-based situation, where she fully expected to be in the child/children's lives until her death. Everyone can make promises at the beginning but no one can force this by law. See the Drewitt Barlows and their first surrogate mother who was adored up and promised lifelong friendship until she gave birth to their first set of twins, and then dropped within a few weeks of their birth. I wouldn't expect you to know about her side of the story as you have only heard what you have been told by the commissioning parents and witnessed the children's behaviour. Depending on how close you are, you may only see their best behaviour and not know their inner most feelings (of the children, not the parents).
One surrogate born adult has said that the birthday cards from their parents every year feels like a reminder of the pay check to their biological mother. I'm not suggesting for a moment that every surrogate born child feels that way, but for even one adult to feel that way (they didn't feel this way as a child) is sad, I think we all can acknowledge that and that not everyone thinks or feels the same. This thread alone is an example of that.