If you are on android... Yeah, by uninstalling the game you lost your saves.
If you download the new apk and install on top of the other one you get to keep your saves.
There is a way to backup saves (or load someone else's)
But you need to know how to use a file manager.
Solid Explorer is recommended.
The file path is:
Android/data/com.domain.corruptedkingdoms/files/saves
Copy the contents somewhere else to backup, or put the files back in.
You can probably get someone else's save in the discord server tho.