I can't program, but I can think, I solved this issue in excel by ordering a list alphabetically, check if row n = row n-1, delete if it does. Reorder by date/time, publish.
That manual process applied to a spreadsheet on your laptop is one thing. Managing data at scale in an automated fashion in an online application with a large number of concurrent users is a whole different context.
But hey, how hard can it be? It works on your laptop.
I can't program, but I can think, I solved this issue in excel by ordering a list alphabetically, check if row n = row n-1, delete if it does. Reorder by date/time, publish.