I posted a feature request before to get the new feature, “text button” to fire the action etc. While I wait for the time it happens, I come up with a workaround to get the some sort of action button UI.
The trick is rather simple and not difficult to arrange. Action button is just a button for Enum type data field, and only one (1) option is made available all the time. Once the app user hit the button, it is appsheet default "buggie” behavior where it clears the field value. Then we can associate action, such as sending email, alert, notification, change value whatsort ever, which is fired through the workflow as well.
And twisting this trick further, by making this enum field to “required” then the button turns to be “unclickable” button, but which makes the text values standing out.
I made qucik sample app for community.
This is not perfect solutions, as it requires a bit of time to toggle the button (not super responsible) , as this tricks involves workflow to be fired on the backend, but it is alway better than nothing.