This question gets asked a lot. Currently on the devs twitter account, he's regulary posting his new passion for 3D printing. He also sometimes posts some pixel art. But literally zero news or announcements about a new game. If I remember correctly there was a dlc for a vampire survivors-like game accounced which would've featured the cast from their games. But I don't know the current stand on that. And he also claimed to focus on sfw games after Winter Memories 2. So either he is hiding the whole development of his new game or we simply will never get one.
Not that it'd mattered because if I recall correctly he was thinking of making a SFW game next anyway. Real shame though... it's always the good ones that leave.