Does it make a difference if I buy it from steam instead of from here? Will there be any differences in content now or in the future? I do not want to miss out on anything
The builds are identical, the only difference for you is the platform you'll be using to download and play the game, and if you live in Germany or China the game is inaccessible on Steam due to laws around mature games. And since you can get a Steam key for the game here on Itch.io, you can buy once and get the game on both platforms.
We have no plans in selling different content on the two storefronts, either.