Hard to say if it will release on Itch cause I heard some R18 Games got denied that ability. I do plan to try and release the game on more stores then just Steam and I am in the debate about releasing the game in SFW mode with NSFW mode require an off-site download. So don't have a full answer but I am planning to find ways to make the game available for sale in places like Germany.
I would say make a rank on Patreon where we get a steam key because of this problem. That is the best way for those in germany to get the game on steam. Make the Patreon rank for example the same price as the steam price! Would get you also more then on steam because of the 30% you pay to steam. But im honestly not sure how you get steam key's for your game is something i should read in to my self. :D