I use Shimano M324 pedals which have SPD on one side and a normal platform on the other. Shoes are Shimano CT80, they are about as good as it gets for walking, which means OK if on very smooth and clean surfaces. I can get around just fine wearing them in most conditions, but they're not something I would ever considering wearing all day for work unless always on carpet.
If changing shoes isn't an option, I would forgo clipless and choose platform pedals that work with your preferred footwear.