This is from Daedalic support for Deponia Doomsday
You can find your savegames here:
Windows 7/8/10: C:\Users\*username*\AppData\Local\Daedalic Entertainment GmbH\Deponia 4\Savegames\
Mac (bought on Steam): /*user*/Library/Application Support/Daedalic Entertainment GmbH/Deponia 4/Savegames/
Mac (bought in the App Store or other online stores): /Users/*user*/Library/Containers/de.daedalic.deponia4.mac/Data/Library/Application Support/Daedalic Entertainment GmbH/Savegames/
Linux: /home/*user*/.local/share/Daedalic Entertainment GmbH/Deponia 4/Savegames