Rinse, hull, and roughly chop the strawberries.
Toss strawberries with sugar and lemon juice in a bowl. Let stand 10 minutes.
Blend half the macerated berries with some juices until smooth; keep the rest chunky.
Stir condensed milk, vanilla, and salt together in a large mixing bowl.
Whip the cold heavy cream to stiff peaks with a mixer.
Fold the whipped cream into the condensed milk mixture in two additions until no streaks remain.
Swirl in the strawberry puree, then gently fold in the remaining chopped berries.
Scrape into a loaf pan, cover, and freeze until firm, 4–6 hours or overnight.