I don't think the force argument is a very good analogy. Except for some edge cases (e.g. rape), most pregnancies occur because the person who is pregnant voluntarily participated in an act knowing there was some amount of risk of pregnancy occurring. In other words, they did something that caused it to happen. It isn't the baby's fault who arguably now has the right to life (which is the most important right you can have in my view). The problem with your first argument is that you could apply it to a child who is 6 years old if you wanted to (which dovetails into your second example...which doesn't resolve ethical problems at all...just legal ones).
Having said all that, except for perhaps prohibiting most late term abortions, I don't think the state being involved will do more good than harm.
Consider two gay men copulating, they started off consensually but now the one on the bottom wants to stop, does he have a right to use force to get the other fellow out?
Sure, but that's a piss poor analogy. The baby doesn't have any choice in the matter.
in my analogy does the top? no right? he can GTFO or face the consequences.
Again, the baby has no such choice.
yeah, that's right, it doesn't, which is probably good since a fetus has no agency.
I don't know what you mean by agency in this context.
the ability to make choices for oneself