Heat fruits in a small pot over medium-high heat, stirring occasionally, until the fruits begin to break down, about 10 minutes.

Use a wooden spoon to mash the fruit to your desired consistency.

Stir in the chia seeds, lemon juice, and sweetener until combined.

Remove from heat and let cool for 5 minutes.

The jam will thicken as it cools.

Serve immediately, or transfer the jam to a sealed container and refrigerate it for up to 1 week, or freeze it for up to 3 months.