If you feel, that levitating dirt doesn't match style of this game, but option with dirt falling sideways and provoking avalanches is too harsh (and also may cause server lags)? 

This simple mod is for you. In standard mode dirt will fall, but only vertically, if not supported from underneath. No dirt ceilings (use cob or rammed earth), but possible to make dirt walls.

Mod change soil stability, depend on game block gravity settings: if "Sand and gravel" is chosen (like default for Standard preset), it add soil gravity, but without sideways unstability provoked by walking, like for sand or gravel.

If "Sand, gravel and soil with sideways instability" is chosen (like in Wilderness Survival preset), probability of dirt avalanche exists but is decreased, forest floor is always stable (no ugly hoovering trees), but packed dirt and arid packed dirt are not suitable to build cellings (but no sideways instablity, walls are ok). Rammed earth, mud bricks etc, are unaffected and alway stable.

Soil behavior differences between vanilla and this mod are shown on pictures, depending on soil stability (blockGravity server setting).

Reference, what was changed:

Usage: current version functionality depend on  "blockGravity" setting. It add moderate dirt physics to standard game settings or tweak dirt physics for "hardcore" game settings.

P.S. In case of Wilderness Survival mode, I recommend to use Fully Packed mod https://news.kalataka.ru/show/mod/31359 as a companion, for better game balance (packed dirt have better stability than dirt, rammed earth have absolute stability, thus recipies should be more expensive)