A setting I believe is new in iOS 18 that I haven't seen mentioned: VoiceOver -> Rotor -> Change Rotor with Item, the description for which reads:
"Changes the selected rotor based on the VoiceOver-focused item."
This sounds like a great thing to turn off in certain activities, e.g. the rotor switching to "Actions" each time you swipe in Mail or Dystopia can be frustrating. Unfortunately, it doesn't seem to be one of the settings that's editable on a per-activity basis, limiting its usefulness. I'm not sure I want to turn it off system-wide.
(Edit: this apparently isn't new in iOS 18, just new to me.)