When the system opens the LPG configuration page it needs to determine the set of input params. For this it needs to determine the list of potential logics driving the calculations on a line item level which can take a significant amount of time.
If your setup does not override the default logic on product level, you can skip this lookup phase and improve performance.
To do this, go to Advanced Configuration Options and add the property doNotUserPerProductFormulasInLists with its value set to 'true'. With this setting, the application will avoid scanning and using logics defined on product level in Price Lists, LPGs and Simulations. I.e., the 3-step calculation logic hierarchy (product → list override → global logic) is reduced to 2 (list override → global logic).
Note: It does NOT affect the formulamanager.execute endpoint, etc.!