Brendan,
My experience was similar to yours. Maybe not as many virtual write-ins, but
many perplexing head-scratchers. "Way, way outside the box" indeed!
Thanks to Tramp, one of the setters I find especially difficult, for an extremely witty and challenging puzzle! Couple of naughty entries of the kind we expect from a certain frequent Prize setter.
I have no idea of the parsing for 19, which is one reason why I didn't want to start the thread. 🤣 My vague and not really satisfactory parsing of 6 is a three-letter "hole" surrounding 2 single letters.
FOI 21. LOI (in grid) 13, though 19 remains unparsed.
Too many good clues to list!
Co-COD 20, 16, 26 and 17. (14,24) gets mention for the sheer challenge.