How does having children work as a trans male in the UK?

So I can't have blood-related kids because I've had a hysto, but I was wondering if someone could give all the facts under just one post. Im going into this under the assumption that you're required to have a GRC to be labelled as a father, so dont worry about putting about he GRC being required unless there's some weird way the law works around it all.

Can a trans man who is carry a baby be labelled as a father on the birth certificate? Or can it only be the mother because of carrying the baby?

Can a trans man who is adopting a baby be labelled as a father on the birth certificate?

Can a trans man who has used a surrogate, but his own eggs, be labelled as the father on the birth certificate?

Can a trans man who has already had a blood-related kid be labelled as the father on a future adopted child's birth certificate?

I assume these questions would be the same for trans women who have decided the same pathways, just with sperm instead.