My Cities: Skylines cities are all gone!

Every time Steam updates, when I click on the desktop shortcut to open the game, Steam opens a box asking if I would like to install Cities: Skylines. I have not found any way around this. This means that whenever Steam updates, ALL of my progress is completely lost. I have tried going to Steam>Settings>Downloads>Steam Library Folders>Program FilesSteam then selecting Repair Library Folder. I also have gone to Program Files > Steam > steamapps > common > Cities_Skylines then running "Cities". All these direct me to the install box. Is there anyway at all to be able to play C:S with my cities?

Update:

Now it has happened to a different game as well, Home Wars! (https://store.steampowered.com/app/645790/Home_Wars/) Please help me, this is getting outrageous!!