In a saucepan over medium heat, combine sliced ripe strawberries, sugar, and water. Cook for about 30 minutes, stirring occasionally, until strawberries soften and release juices. Strain syrup into a bowl and let it cool to room temperature.

Bring 2 cups of filtered water to a rolling boil in a kettle. Add black tea bags and steep for 5 minutes. Remove tea bags and stir in remaining sugar until fully dissolved.

In a large pitcher, pour cooled strawberry syrup, brewed tea, and remaining 2 cups of water. Add lemon juice and stir well.

Fill glasses with ice cubes or frozen strawberry slices. Pour the strawberry tea mixture over the ice. Garnish with fresh mint leaves and additional strawberry slices.