I have a 90 mm refractor (Celestron). It is one of my favourites because of its "grab 'n go" capability - I can carry it on my shoulder

Recently I took it to the Bunya Mountains as it is small enough to fit in car with all that other stuff for 3 nights, which would last for 3 months.
As you say, for the Moon, you need no bigger scope - I ended up looking at the Moon in the morning, and it was just as exciting as looking through my 12" truss Dob.
Try a few open clusters

- notably NGC 4755 the Jewel box and some in Carina this time of year. Also try looking at doubles - plenty of beauts around Crux and Carena.(Alpha Crux, Alpha Centaurus etc.) Nothing wrong with the 90 mm though. I just love refractors, and they are so RUGGED. I dropped one on a concrete floor once - no damage at all

They are easy to get good focus as well and no collimation worries.