Brew 2 cups of strong tea and let it cool to room temperature.

Pour 4 cups of water into a large pot and bring to a boil over high heat.

Add 2 cups of sugar to the boiling water and stir continuously for about 2 minutes until the sugar dissolves completely.

Remove the pot from heat and let the simple syrup cool to room temperature, about 30 minutes.

While the syrup cools, juice the oranges, lemons, and limes to yield 1 cup orange juice, 1/2 cup lemon juice, and 1/2 cup lime juice and strain through a fine-mesh sieve.

Pour the cooled simple syrup, cooled tea, 1 cup of brandy, and all citrus juices into a 9x13-inch freezer-safe container and stir thoroughly.

Cover the container with plastic wrap or a freezer-safe lid and freeze for at least 6 hours or overnight for best texture.

After 6 hours, remove the container and break up any frozen sections with a fork, stirring well to incorporate all icy parts.

Repeat the freezing and stirring process every 6 hours for the first 24 hours to prevent large ice crystals.

Once fully frozen, scoop the slush into chilled glasses and serve immediately, optionally topping with a splash of club soda or ginger ale.