Let's Suppose There Were No Natural Caves Before the Flood

This is one of Robert Carters argument's against the Neanderthals being pre-Flood:

• Caves were formed after the Flood.
• But Neanderthals were buried in caves.
• So, Neanderthals were buried after the Flood.

Now, watch this video about Ancient Lycia:

Wonders of The Lost Lycian Civilization
Street Gems | 12 July 2023
https://www.youtube.com/watch?v=ZAmos7gsrUk

So, wild hunch, what if the Neanderthal burials are really rock tombs, as in Ancient Lycia, with carved caves, and the Flood added irregularies that now make the caves seem natural?
/Hans Georg Lundahl