Essentially, Kiss×sis. But PG (no hentai, and don't think there was anything ecchi even), no "we are stepsiblings, so society does not like this" flavor and... Probably taking things a bit too serious. Not just the narrative itself, which I would normally commend, since they are clearly writing the characters much better than some borderline hentai OVA could dream of. I am talking more about overall approach to the situation, that characters are in, which could have been resolved by them... Talking to each other.
I get it, if they did, then there would be no story, probably, but I think it is safe to say, that that's where they will end up. Maybe even in the 2nd episode. And maybe this was the point of it all: to build up the pressure, and then to release it, as if it was an orgasm. But there is a problem with both approaches: if drama will go away in 2nd episode, then everything else may become boring, but if it does not - it may become tiring.
Honestly, I think they should have taken approach closer to what "Domestic Girlfriend" had. It had a more balanced palette of drama and light-hearted love comedy. Far from perfect, and possibly a bit too dragged out (and with a really bad ending, to be honest), but it did show more of the happy (and mundane) times of the relationships from the start, while adding drama where it made a bit more sense.
You can try it out, of course, but this does not feel like my cup of tea, or at least not something, that I want to watch at the moment.