Hi Brian!
I'm sorry to hear about your phone. My guess is that there's sand still blocking the port and/or that it needs more time to dry out. I've submerged my S7 edge in a bathtub and it took 2 days for the speakers to sound clear and about a day and a half for the charging port to function again. In the meantime, I used wireless charging.
To clean out any remaining sand, I'd use a can of compressed air (be sure to keep it upright). If you've cleaned it out sufficiently and are confident you dried it out as much as possible, there's a chance the charging port was damaged to the point of needing repaired. We do sell the [product|IF329-015|Galaxy S7 edge charging daughter board] which can revive your port but fingers crossed it just needs a little more time to recoup.
If you do end up repairing it, keep in mind the phone will no longer be waterproof once breaking the adhesive seal ;(
Good luck!