I highly recommend giving the nursery a chance, even for just an hour at a time. The nursery staff I've encountered were really great. On our last cruise our 2 year old was *not* sold on the idea of being apart from us (she never is) but we took her during open house on the first day and used that time to help get her acclimated both to the space and the staff. We ended up being able to leave her there for an additional hour alone which was more than I was hoping for honestly. I credit the hard work of the staff for making it possible. I expressed my concern to them about her being unhappy without us, and they messaged us multiple times through the app with status updates letting us know how she was doing, that she'd settled down and was playing happily, etc. You could do your first hour without any actual plans for the time (like a tasting or Palo) so that if it doesn't go well, you can easily pick your child up. You won't get charged for hours you don't use if you end up having to pick your child up early due to being unhappy (I asked, lol).
Which ship are you on? The Magic has (or at least it used to) a little play area adjacent to one of the lounges which we made a lot of use out of with our first. Unfortunately I haven't found anything equivalent on any of the other ships we've been on.
One other idea -- you could room service the cheese plate and some wine (or bring drinks back from a lounge) and enjoy some quiet time in your room after the kiddo goes to bed. This will work better obviously if your kid sleeps well while you're still up or if you have a verandah you could sneak onto.
Good luck and I hope you have a wonderful cruise!