I want to save or load the data list in bubble DB to external mysql DB

I want to save or load the data list in bubble DB to external mysql DB (synchronization).

The problem is that the length of this list is variable. Previously, when the length was fixed, I used the external server RestAPI to send and receive data. However, since the length of the data list is variable, I don’t know how to process the data. This is especially difficult because it is impossible to work with loops in bubbles. Even if you import the data list into a bubble, it is difficult to repeatedly use the create a things action.

In conclusion, my question is this: What is the best way to save or load a variable-length data list from an external DB?