Vocabulary for dictation in MacOS and iOS

As I am starting to use MacOS Voice Control for dictation, I've also been playing with it on my iOS devices (slow uptake of this tech due to longtime work-related privacy concerns).

How can I share my vocabulary additions and customizations between Voice Control and iOS devices? Is this something that only Siri can do?

And here is a frustration with these forums: this is device-agnostic, not specific to my iPhone or iPad but to the integration across devices. Irritating to be forced to one device and one topic area because this is a pan-device question.