Hello,
You are tagfiddling again :)
Previously I used to separate out plaques from plates - you can see that at https://map.atownsend.org.uk/maps/map/map.html#18/-25.00904/135.17758 .  Tag changes should be discussed in the forum, especially if there are data consumers who are going to be affected - something that you can see at https://taginfo.openstreetmap.org/tags/memorial=plate#projects .
On an individual basis it's certainly possible to argue that "plaque" is the better tag - this one is https://www.iwm.org.uk/memorials/item/memorial/44738 , and I'd have mapped that as a plaque to start with, but mass changes should be discussed - something that you seem to have trouble doing: https://www.openstreetmap.org/user/geozeisig/blocks .
Best Regards,
Andy

