I also found this harder than usual. Thanks to Everyman for a well-crafted challenge.
Good spot on the &lit, though I have no idea whether it's the first.
I also noticed two longish hiddens, unusual to me (back when I did the Times puzzles pre-paywall, I got the impression the Times only allowed one hidden per grid).
My COD was also 1d! Runners-up in order 19, 3, 2, 9, 13 and 5.
FOI 9, LOI 14 (write-in but needed Google to verify).
Is there a rhyming pair? Two longish clues end in the same letter but I don't consider it a rhyme.
15a and 18 (often involved in similar wordplay) are a funny coupling. π
In the hint category: two long anags across, one down.
BTW, I'm seeing multiple blank lines weirdly inserted into various forum posts, including brendan@1.