I used to do shoulder press with dumbbells. Was at about 17.5kg with a single low-rep set at 20kg, and it took me months to get to that point. Decided to move to overhead press at an equivalent weight, which was tough at first. But, after about a month I progressed from 35kg to 50kg, then another month put me up to 60kg. By that point the dumbbells had become just as easy to use, and I gradually phased out bothering to use them for stabilisation (even though it's a single solid weight, the weight is separated by several feet and both arms have to work together to support one another- if one arm lags behind, the other is dragged down with it). I'm currently shoulder pressing 85kg for 5 reps, and probably wouldn't be if I hadn't moved to the barbell.
Similar story for bench press. And for one-arm rows, which I exchanged for pull-ups with a weight belt and can now do multiple sets with 25kg strapped to me (I weigh 80kg); the one-arm row by comparison brought slow, limited progression and has since become rather too easy. And don't get me started on the deadlift and the squat, which dumbbells simply cannot keep up with (find me some 80kg dumbbells for my squat with which I can actually keep good form and we'll talk).
If you have a barbell available, use it. If you want to get the best of both worlds, find exercises for the dumbbells which only the dumbbells can do (of the two pieces of equipment) and which you will gain different benefits from. Flyes for the inner chest; front, side, and rear (most important one, as most shoulder exercises focus on the front, which can lead to hunching problems) lateral raises for shaping the shoulders; etc.