I think this will be applicable if we used a name page with pxResults to source the dropdown , currently i am using the field value property to source the drop down , i do not have a pagelist property to use in obj-sort method , attached doc for reference
I am a little confused. The list that you have shown already shows the results in sorted order
(L, M, N, O). Is that coincidentally showing in the right sorted order?
Unfortunately, I don't have an example written out. But I am attaching help for override sort function as well another community post that together should perhaps help you with attempting to use override sort function. See if it resolves your issue.