From my copy of Gimp 2.10 - fortunately it is script-fu and only a couple of syntax fix for Gimp 3 (although the usual rules apply - no guarantee )
Download - put in your user scripts folder - registers in Filters -> Distorts -> Erase Every Other Row
This one ?
Download - put in your user scripts folder - registers in Filters -> Distorts -> Erase Every Other Row
This one ?