Add the cream cheese, the low carb sugar-free condensed milk, orange extract (if using) and cream to the bowl of a stand mixer (or large mixing bowl if using a hand-held mixer). Mix on medium speed until ingredients are combined, then increase speed to high, scraping down sides as needed. Mix until smooth and creamy.
In a small glass or bowl, combine juice from fruit and stir in gelatine powder. Put the container in microwave and heat for 20-30 seconds, stir and check gelatine has dissolved (nuke a little longer if needed until gelatine dissolves)
Add gelatine mixture and 2/3 of lemon and lime zest (and 2/3 orange zest if not using extract) to cream cheese mixture and mix at medium speed until combined. (Remember to only use 2/3 zest in filling mix and reserve 1/3 for decoration)
Pour cream cheese mixture over top of the cooked base, spread evenly and smooth top with a flat knife. Chill cheesecake in the fridge and allow to set for 2-3 hours.