I had built a map in the 1.8 then wanted to the 1.16 and made a copy of the map. Then I'm in 1.14 on the map and then there was only water where my house was. Could I somehow get onto the copied map?
Yes, by opening the world with 1.9> 1.10> 1.11> 1.12> 1.13> 1.14> 1.16.
No matter which version I open it, there's just water
But I have a copy of the map just I don't know how to get it
Did you open the world one by one in that order?