If the centre channel is too low/the dialogue is difficult to understand, there are a number of things you can try to mitigate that within the Filter design:
Make sure that the Centre is not supporting any other Groups.
Raise the overall Centre Group level:
Select the Centre Group.
Right click on the target curve → Convert shelves to control points
3. Drag the whole target curve up by a couple of dBs. You can right click on the control points to remove them - making it easier to draw a flat curve.
4. You could try slightly boosting the 2-5 kHz area which is responsible for dialogue clarity.
5. Calculate and export the filter to a new slot. This filter could then be used as an “enhanced dialogue preset”.
Tip: You can store and load target curves in the Menu → Save/Load target curve.