When 'personhood' begins is very germane to the debate. If you believe it starts at birth, then terminating a pregnancy at any point is a non event (except physically). If, however, you believe it starts earlier (as most do), it does become a conflict of rights with a degree of compromise required balancing the foetus's right to a chance of life vs the mother's bodily autonomy.
No, that doesn't follow. It's not necessary to ascribe personhood to a foetus in order to have laws which govern what happens to it.
The current law does not permit abortion past 24 weeks except in a few very specific circumstances AND the current law does not recognise foetuses as persons. Similarly, we have laws which govern what happens to embryos, and even eggs and sperm, in fertility clinics and research labs. That doesn't mean that embryos have personhood, or that gametes have some sort of semi-personhood. We have laws which govern how we treat animals without ascribing personhood to animals. etc. etc.
Personhood is a huge deal because if the law says you are a person then you have full human rights.
Theoretically there still should not be a conflict of rights between the woman and the foetus because there is no law that permits another person to use your body without your consent, even if they will otherwise die. E.g. you cannot be forced to donate blood or an organ to save someone else's life.
That's not what happens in practice though. As we have seen in NI and in some US states, when the foetus is regognised as a person its rights are treated as more important than the rights of the woman.
As Sally Rooney said, 'If the foetus is a person, it is a person with a vastly expanded set of legal rights, rights available to no other class of citizen: the foetus may make free, non-consensual use of another living person’s uterus and blood supply, and cause permanent, unwanted changes to another person’s body.'
www.lrb.co.uk/the-paper/v40/n10/sally-rooney/an-irish-problem