I really hope someone can help me here!
I'm currently running Mac OS Big Sur on an M1 Mac and and older Macbook Pro, and on both machines, the play action button is always greyed out. Granted, I'm new to Photoshop, but I did use it once or twice before the update. Is there anything I'm doing wrong?
»Is there anything I'm doing wrong?«
Do you think you provided the information that makes answering that question possible?
Could you please post screenshots with the pertinent Panels (Toolbar, Layers, Actions, Options Bar, …) visible?
Is one Action selected in the Actions Panel?
This is an example of what I mean. The action button is greyed out. Also, it doesn't matter which action I select.
In your screenshot no Action is selected, so please select an Action and post a meaningful screenshot.
Just to make sure: To select an Action click on its name in the Actions Panel.
Turn Button Mode off.