Recently, I had to change some settings to the Steam Cloud save system and it seems it caused issues on some mac computers.
If your save disappeared, I cannot give you your exact progress back, but I can give you a save file with all missions unlocked.

Here is what you need to do:

Download the file linked below and place it in your save folder:
Link to save file on Google Drive[drive.google.com]

To do so:
- Go to ~/Library/Application Support/Doot/MinamiLane. This folder is hidden, you'll have to press Command + Shift + . (period) to make the hidden files appear in your Library.
- Place the file there.
- Try to launch the game to see if you have access to all missions. If not, do it again and launch the game without internet first.