I guess something got corrupted or misinterpreted when updating to Sequoia.
What happens if you re-enter the desired shortcuts in Sequoia? Do they work?
P.S. My unsolicited opinion: I think that keyboard shortcuts in System Settings is a sad pathetic concoction implemented in a barbaric, shameful way. Even in 1990s this kind of tool would have looked like a bizarre archaic artifact. I guess it's also unreliable, as we can see from your post. As you probably know anyway, there are quality 3rd-party utilities available. Namely, Keyboard Maestro (albeit not free); but I think there are some free ones around, too.