When you uninstall an app, you have an option to keep or remove your settings. Nothing else is removed. Your projects are stored locally, unless you use network or cloud storage. In either case uninstalling an app should not remove any file you created. What folder was this file kept in? Can you do a search for it?
In any event Backup software is important. Copy projects to another drive just in case of computer failure. You may lose a few steps, but not the entire file.