The simple removal of duplicates, should be trivial. The Advanced filter than tempts that, is unusable the [Read Filter Criteria] is a confusing element and unworkable in all the attempts I've made to make sense of it. No, I don't want to read a manual just to action a simple data fix. It's easier to export and sort+uniq on the commandline that within the product. Very odd design for this. Expecting this still affects later versions too.
Hmm, nothing here actionable. Guess OP is looking for an enhancement... Otherwise it *is* an RTM issue. https://ask.libreoffice.org/en/question/53569/delete-duplicates-in-calc/ or older OOo era https://forum.openoffice.org/en/forum/viewtopic.php?f=9&t=5379#p35891 https://wiki.openoffice.org/wiki/Documentation/How_Tos/Removing_Duplicate_Rows
Seems this was open as an enhancement already... *** This bug has been marked as a duplicate of bug 85976 ***