In this case, the approach can be as follows: instead of using “Go to select page” in the Reference Selector on the parent page, configure it to trigger a Microflow or Nanoflow (On click). Inside that flow, open your own custom selection page that contains Data Grid 2 (as a normal page, not a select page).

On the selection page, add a Select button to the Data Grid 2. This button should call another microflow that links the selected object to the parent context (sets the association) and then closes the page to return the user. This way, you can keep all the advantages of Data Grid 2 without running into the limitations of the standard “Select page” mechanism.