Is the beach nice and Sandy or pebbly?
If you mean San Stefanos NW the beach is sandy and quite flat
If you mean San Stafanos NE the local beaches are stones. someone had put a few loungers out by the sea but it isn't really a sandy beach place. It is a good area to snorkel though and you can hire a small boat which you steer yourself to go to remote spots or even tavernas further along coast.
The beach in San Stefanos NW is sandy. At times you have black sea grass washed up the shore where the hotels are. There is garbage in northern remote areas of the beach. I’ve seen a dead turtle, seagull and hedgehog there. Apart from that it is very nice. You must walk quite a bit to get to deeper waters.