I'm not sure you can reduce this sequence to a single operation, to make it available to Shift R, repeat last operation. Even taking into account that the I inset operation has a 'Depth' setting, which can easily go unnoticed.
But as @moonboots has commented, you can execute the operation on multiple faces simultaneously:
- Set Pivot to 'Individual Origins', and Orientation to 'Normal'
- Set the Inset tool to 'Individual'
- I inset
- E extrude
- S scale faces
The XY guidelines in the last move in the gif are there because I instinctively used S Shift Z to scale, which is actually unnecessary.