@Kelly70 there's a good chance of a kid ending up an angry teen for all sorts of reasons, just by virtue of being a teenager, God knows I was an angry angry teen. Right up till I turned 30 if I'm honest and I knew both my bio parents. It's true that a donor conceived kid might be angry about that but if it's not that, it'll be something else for sure.
A nephew of mine has the most stable, loving, nuclear family and he's constantly angry at them for the most bizarre reasons, we call him the rebel without a cause. He goes on about how he's just got nothing in common with them and they totally don't understand him one bit - typical teenager stuff. His folks are flabbergasted, no matter how nice they are he pushes them away. He will grow out of it eventually 😜
I wonder too if in the future gene mapping will become more commonplace and it may be possible to learn about ancestry even where anonymous donors are used. There was a show on TV a while ago starring Eddie Izzard the comedian where he had his genes mapped right back to Africa and all these little mutations revealed information about his early ancestry, it was fascinating stuff, all from a single blood sample.
Anyway I'm rambling and I can't really talk because I have a bio child within a hetero marriage so we are about as middle of the road vanilla as it gets, but still I do think, as Vixjc said, the bond you get is from being there for every smile and teaching your baby to laugh by doing silly dances, and cuddling them every time they cry and that's not genetics, that's mothering.
Not to negate your concerns, they seem like valid ones to be prepared for, but to me they aren't big enough hurdles to be worth missing out on sharing that love that comes from having a baby and being a mum.