First content update before end of Q3 2021, no concrete dates on the others. although the next biome has been set to be the second release. instead of the 4th.

And it isn't 4 released to full game, it 4 releases to get some of the planned content polish and 1 new biome. There are still at least 2 more biomes to release after all that before full release.

guessing about 2 years before the game leaves EA, just a guess.