Technically, this has been an issue since 1.17-rc2, but regardless if cheats are enabled or not, you cannot use F3 commands, meaning you can't reload texture packs, reload chunks, switch to spectator mode. How did this make it into the full release of 1.17?

The Cause of the Bug

With the bug being caused by new shortcuts in macOS Monterey, on laptops, using FN and a certain key will trigger a shortcut, like FN + A for Finder, FN + N for notifications, etc. Apparently, Minecraft cannot cancel these actions, and therefore is triggering this bug.

As of right now, you can disable FN + Q in Keyboard settings, which will allow you to use FN+F3+Q again in-game.