Minecraft lost map

So my Minecraft survival map was lost. I didn’t do anything special and my computer was completely fine. At least the last time I played it’s completely fine.

But when I woke up this morning and I saw my map was gone, in the game. Then I went to check my file and my back up is still there. So I try to remove it from the ‘saves’ file and put it back in, nothing happened.

I tried to create a new map and replace the information inside with my old map, nothing happened. What should I do?

Just to clarify, my backup was saved outside of the saves folder and I’m trying to take a map out and copy it back in?