Place tea bags into a bowl and pour four cups of boiling water over them. Leave to steep for several minutes before discarding the tea bags.
To make the infused simple syrup, combine a quarter cup of water, honey, lemongrass, and cinnamon sticks in a small saucepan and place over medium heat. Simmer, stirring occasionally, until mixture is heated through and starts to thicken, approximately 4-5 minutes.
Remove from heat and pour through a fine-mesh strainer to separate the solids from the liquid. Discard solids and set the remaining simple syrup aside to cool.
Pour the brewed tea, lemon juice, and remaining cup of water in a large pitcher. Add infused simple syrup, to taste, and stir to combine.
To serve, fill four chilled glasses with ice before adding the sweetened iced tea mixture.
Garnish with lemon slices and sprigs of fresh mint, if using, and serve immediately. Enjoy!