I don't own /condense but if I ever get it this would be amazing. I think this wasn't applied at first because it is 1 2x2 square, not a 3x3
I know, kuke said that you aren't able to take Quartz Blocks Into Quartz, so I said that is not what the suggestion is about
/condense by itself will only work on blocks that go both ways. For items that only go from item to block, use /condense [item] or /condense all. This is to prevent accidentally condensing things you can't turn back. "/condense quartz" should function like you're requesting.