It’s definitely possible to keep a group of 3–4 datnoids together, but the key is tank size and individual temperament.
Datnoids are semi-aggressive and territorial, so when kept in groups, odd numbers (like 3 or 5) usually work better than even ones to help reduce direct pairing off and bullying. A group of 3–4 can work if they’re raised together from a young age and you provide plenty of space, hiding spots, and visual breaks (like driftwood, rocks, or plants).
Make sure your tank is large enough—ideally 180 gallons or more for a group, depending on species and size. Also, keep a close eye for aggression. Sometimes, one fish becomes dominant and bullies the others, and separating them might be needed.
In short, yes—it can be stable, but give them room and watch for signs of stress or bullying.