I may have just figured out where this huge save size may have come from. I used a command to reveal the map around the player, and I am not sure anymore what radius I specified. (So, in short, it's probably my fault..) I will try to load the map again and see how much of it is actually generated to ...

I recently installed 0.17.9 and started a new game.
I spent about 17h on it and installed a few mods, but now it has become completely unusable for me.
The save file is about 1.2G, the level.dat is 2.1G, and every time I load the map, it fills up my 16GB of RAM almost instantly and (obviously) the ...