Use loose-leaf tea with a steel infuser or a teapot, or choose brands that state their bags are plastic-free and unbleached. Compost the leaves.
A heat-sealed tea bag contains a small amount of polypropylene, and premium pyramid bags are often nylon or PLA mesh; at roughly 0.15 g each, 500 cups a year is about 75 g, plus the microplastic released into the cup.
The catch: PLA bags marketed as compostable need industrial composting; University College London (UCL)'s Big Compost Experiment found 60 percent of home-compostable-labelled items were still clearly visible after home composting.