Combine strawberries, sugar, and lemon juice in a saucepan. Simmer 10–15 minutes, stirring and mashing, until reduced to about 3/4 cup of thick puree.
Transfer puree to a shallow bowl and refrigerate until completely cold, about 1 hour. Do not mix warm fruit into whipped cream.
Stir condensed milk, vanilla, salt, and the cold strawberry puree together in a large bowl. Make sure the fruit is evenly dispersed.
Whip cold heavy cream in a separate chilled bowl to stiff peaks, stopping before it becomes grainy or begins turning to butter.
Fold one-third of the cream into the strawberry mixture to lighten it. Gently fold in the rest until no white streaks remain.
Scrape into a freezer-safe loaf pan or container and level gently. Press food-safe wrapping onto the surface and cover tightly.
Freeze at least 6 hours, preferably overnight, until firm enough to scoop. Keep the container flat while the mixture freezes.
Soften briefly at room temperature before serving. Scoop with a sturdy ice cream scoop and return remaining ice cream to the freezer promptly.
