I have a problem like this too. I have "Undecided" dramas. Ones I am not completely uninterested in, but also ones I'm not sure if I even want to watch. I wish I could put them on a completely separate list than our current options of plan to watch, on hold, or not interested.
Right now, I just have them on my plan to watch list, ser as low priority, but I feel like they are cluttering my plan to watch list. The only advice I was given before was to move them all onto a custom list, but that was not helpful to me as I still wanted the pencil icon beside the title to show I already had looked at the title before. But maybe it could be helpful for you.