My suggestion: either you create Columns of the Type WIDGET where you can select other tables AND select a widget for it…
or maybe when editing a Card Widget Layout, you simply can move another widget on the screen INSIDE the card widget, as if it was another field.
in the example above, a Risk Register, and then INSIDE the Risk Record, several Risk Analysys of THAT risk in a table format, and below a card list for Action Plans for THAT risk.