Was the chamber ever reused (for other purposes such as research of Slytherin and Basilisk) after Ron and Hermione got the Basilisk fang from inside?
We don't know. None of the references to the post-Battle of Hogwarts future (the ending of Deathly Hallows, various articles on Pottermore, the Cursed Child script) mention the fate of the Chamber of Secrets.
That being said, in the absence of a large basilisk to guard it, and since its location is known by at least half a dozen people including the Hogwarts senior staff and the trio, the room is now merely a large sub-basement, albeit one with a fancy lock.
Presumably the House Elves are able to teleport to it freely and can therefore use it as a cold meat cellar / subterranean dance club