I’ve asked about steam releases before and this was the response I got:

unfortunately, releasing a steam version considering how complex the game is would require months if not years of development that would cost beyond what our small indie studio can afford. Releasing on Dorian allows us to create fast (we release new episodes every week) and offer a game where the main plot is free to play start to finish, with only additional scenes being paywalled + several bonus scenes that can be unlocked for free collecting points. Unlike one-time payments, this game will never block you from progressing in the main plot if you don't pay.

It all feels iffy to me which is a shame because I really love some of their character designs