Modding is unsupported and at least a greater than zero risk. However, while so far the devs have not done it, the EA game is in flux and at some point a big update or the 1.0 release may also break old save games. Modding adds to the risk, though.

The bottom line is that you are not ensured a world that will survive through to the release of the game. Most likely, given their approach so far, you will have that.

The real threats to your worlds and characters are outside the game, honestly. Messing up cloud saves can lose progress or entire worlds, for example.

So, honestly, the only advice I have is to set up a daily backup of your game files if you want to have a long lived world, and when in game, log out once in a while to force saving and updating of your auto backups (game provided) or manuals (your own backups).