On Mac, you can do ⌘+T to bring up your Tapback responses in Messages and then you can use the number keys, 1-6, to select your reaction. 🤯 Get ready for lots of ❤️ and 👍🏻 everyone…
It also works on iPad.
What I’d really like is to be able to choose a Tapback right from the notification, especially if the Messages app isn’t even open.