No G30 doesn’t have a reputation for brittle unions. You are thinking of G41 I think. G30 may need support. It depends on how you train it, the cultivar and the age. For central leader trained trees they will be self supporting at some point. The tree bears really early for a semi-dwarf and the high crop load will mean it will need support for a period of time. But M7 needs support too in many cases.
A thread about G30 needing support-