In threads about the impact of the Supreme Court ruling it has been mentioned that the only people actually impacted by this, ie that sex in the act means biology, are those people who have gone through the process of getting a GRC. ie all those who go one about having an identity or whatever, the ruling makes no difference to as they aren't recognised by any law.
https://www.libdemvoice.org/why-are-uk-trans-people-upset-78192.html