You can dismiss an incoming message by double-pressing the right scroll wheel on the steering wheel, rather than swiping the screen.
To ensure your Tesla (like a 2020 Model 3 or Model Y) can handle texts, you must enable specific settings on both the car and your phone: Tesla (2020)
Instead of scattered notifications, all messages from the same sender are combined into a single conversation thread. You can dismiss an incoming message by double-pressing