The point has been made that ditching directly (more or less) towards a beach so as to slide on to, and then come to a stop on, the beach is implausible because of the impossibility of judging the final descent and touchdown point to enable this to happen.
I suspect that the only plausible scenario is a very wide, very long, straight beach, with a very shallow slope seawards, and an approach angle to the beach of, say, 5%-15%. This would give a fair margin for error, with a reasonable chance of ending up out of the water, in between the water's edge and the top of the beach.
But finding that beach just when you need it for a forced landing, and then being able to position accurately for the approach and touchdown, would require huge amounts of luck.
But I don't fly B777s, and that may be a daft idea to anyone who does.