What then if I need to insert multiple rows at once in a table? I have to insert the rows one by one and at the end set the relation on the parent table? Please tell me that is there another way
I am sorry you feel this way. We have analyzed behavior of multiple (very different) apps before we made that change. The change is needed in order to allow better scalability of the service.
We will continue running v3 since there are paying customers on that backend. Those apps will stay. Apps on the free plan on v3 will have to either migrate to v4 or upgrade to a paid plan.