So. In case you hadn't heard, 2020 is the two-hundred-fiftieth anniversary of LUDWIG van Beethoven's birth. We don't know the actual date of his birth, only that he was baptized on December 17, and since typically that happened the day after birth, December 16 is often thought to be the day in question.
Just for the record, I do really love and admire much of his music. His pieces are typically beautifully structured, with a wonderful sense of inevitability about how melodies and sections are built and how they come to fruition. I also appreciate how his working process is so well documented, so we know just how much work he put into making his music work the way he wanted it to.
I don't love his own self-image and the myth that has built around him of the tortured genius. No doubt going DEAF was an incredible burden to bear, but he continued to compose astonishing music despite that. And most of his torture was self-inflicted. It has contributed to the concept that genius has to come out of depression or loss or something like that. Whereas I think it mostly comes from hard work applied to some natural talent.
Anyway, I'll get down from my soapbox. The puzzle acknowledges BEETHOVENSFIFTH symphony in CMINOR, whose theme is often thought to represent FATE. We've seen in a previous puzzle, I think, the G G G EFLAT, although I like how the notes are presented here as if there is a musical staff starting in the fourth row and then proceeding on every other row until it ends on the eleventh row (thus symmetrically placed in the grid). Also, 2D: Key to this puzzle's theme? is a brilliant twist on a revealer.
The theme material is presented asymmetrically, and outside of the OBOE (and maybe AIDA? and why not ACH?) it feels a little sparse. On the other hand, we get the outstanding 18A: Items that are hard to throw away? (BOOMERANGS) and 58A: That's gnus to me! (WILDEBEEST). That last reminds me of the very odd Monty Python sketch (are there any other kinds?) about "Confuse-a-cat," a new product that does just what it says. At the end they rattle off multiple other related products, and one of them is "Bewilder-a-beest."
Anyhoo, I'll just end on noting that 1D is referred to by 22A, and this cross-reference works for me, both because the clue number is higher, and because it naturally comes later in the solve.